Chapter 1
College Algebra Essentials · 725 exercises
Problem 128
Determine whether each statement makes sense or does not make sense, and explain your reasoning. When I solve an equation that is quadratic in form, it's important to write down the substitution that I am making.
3 step solution
Problem 128
Use the strategy for solving word problems, modeling the verbal conditions of the problem with a linear inequality. An elevator at a construction site has a maximum capacity of 2800 pounds. If the elevator operator weighs 265 pounds and each cement bag weighs 65 pounds, how many bags of cement can be safely lifted on the elevator in one trip?
4 step solution
Problem 129
In Exercises \(127-130,\) solve each equation by the method of your choice. $$ \sqrt{2} x^{2}+3 x-2 \sqrt{2}=0 $$
4 step solution
Problem 129
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement. Find \(b\) such that \(\frac{7 x+4}{b}+13=x\) has a solution set given by \(\\{-6\\}\).
4 step solution
Problem 129
Use the strategy for solving word problems, modeling the verbal conditions of the problem with a linear inequality. An elevator at a construction site has a maximum capacity of 3000 pounds. If the elevator operator weighs 245 pounds and each cement bag weighs 95 pounds, how many bags of cement can be safely lifted on the elevator in one trip?
5 step solution
Problem 130
In Exercises \(127-130,\) solve each equation by the method of your choice. $$ \sqrt{3} x^{2}+6 x+7 \sqrt{3}=0 $$
4 step solution
Problem 130
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement. The equations \(\sqrt{x+4}=-5\) and \(x+4=25\) have the same solution set.
2 step solution
Problem 130
Use the strategy for solving word problems, modeling the verbal conditions of the problem with a linear inequality. To earn an A in a course, you must have a final average of at least \(90 \% .\) On the first four examinations, you have grades of \(86 \%, 88 \%, 92 \%,\) and \(84 \% .\) If the final examination counts as two grades, what must you get on the final to earn an A in the course?
3 step solution
Problem 131
In a round-robin chess tournament, each player is paired with every other player once. The formula $$N=\frac{x^{2}-x}{2}$$ models the number of chess games, \(N,\) that must be played in a round-robin tournament with \(x\) chess players. Use this formula to solve Exercises \(131-132\). In a round-robin chess tournament, 21 games were played. How many players were entered in the tournament?
3 step solution
Problem 131
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement. To solve \(x-9 \sqrt{x}+14=0,\) we let \(\sqrt{u}=x\)
3 step solution
Problem 131
Jane's salary exceeds Jim's by \(\$ 150\) per week. If \(x\) represents Jim's weekly salary, write an algebraic expression that models Jane's weekly salary.
3 step solution
Problem 131
Use the strategy for solving word problems, modeling the verbal conditions of the problem with a linear inequality. On two examinations, you have grades of 86 and \(88 .\) There is an optional final examination, which counts as one grade. You decide to take the final in order to get a course grade of A, meaning a final average of at least 90. a. What must you get on the final to earn an A in the course? b. By taking the final, if you do poorly, you might risk the B that you have in the course based on the first two exam grades. If your final average is less than \(80,\) you will lose your B in the course. Describe the grades on the final that will cause this to happen.
4 step solution
Problem 132
In a round-robin chess tournament, each player is paired with every other player once. The formula $$N=\frac{x^{2}-x}{2}$$ models the number of chess games, \(N,\) that must be played in a round-robin tournament with \(x\) chess players. Use this formula to solve Exercises \(131-132\). In a round-robin chess tournament, 36 games were played. How many players were entered in the tournament?
6 step solution
Problem 132
A telephone texting plan has a monthly fee of \(\$ 20\) with a charge of \(\$ 0.05\) per text. Write an algebraic that models the plan's monthly cost for \(x\) text messages.
3 step solution
Problem 132
Use the strategy for solving word problems, modeling the verbal conditions of the problem with a linear inequality. Parts for an automobile repair cost \(\$ 175 .\) The mechanic charges \(\$ 34\) per hour. If you receive an estimate for at least \(\$ 226\) and at most \(\$ 294\) for fixing the car, what is the time interval that the mechanic will be working on the job?
3 step solution
Problem 133
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement. $$\text { Solve: } \sqrt{6 x-2}=\sqrt{2 x+3}-\sqrt{4 x-1}$$
4 step solution
Problem 133
If the width of a rectangle is represented by \(x\) and the length is represented by \(x+200,\) write a simplified algebraic expression that models the rectangle's perimeter.
3 step solution
Problem 133
Use the strategy for solving word problems, modeling the verbal conditions of the problem with a linear inequality. The toll to a bridge is \(\$ 3.00 .\) A three-month pass costs \(\$ 7.50\) and reduces the toll to \(\$ 0.50 .\) A six-month pass costs \(\$ 30\) and permits crossing the bridge for no additional fee. How many crossings per three-month period does it take for the three month pass to be the best deal?
4 step solution
Problem 134
When graphing the solutions of an inequality, what does a parenthesis signify? What does a square bracket signify?
3 step solution
Problem 135
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement. $$\text { Solve for } x: \sqrt[3]{x \sqrt{x}}=9$$
6 step solution
Problem 135
Describe ways in which solving a linear inequality is similar to solving a linear equation.
4 step solution
Problem 136
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement. $$\text { Solve for } x: x^{\frac{5}{6}}+x^{\frac{2}{3}}-2 x^{\frac{1}{2}}=0$$
4 step solution
Problem 136
Describe ways in which solving a linear inequality is different than solving a linear equation.
4 step solution
Problem 137
Will help you prepare for the material covered in the next section. Is \(-1\) a solution of \(3-2 x \leq 11 ?\)
4 step solution
Problem 137
What is a compound inequality and how is it solved?
4 step solution
Problem 138
Will help you prepare for the material covered in the next section. $$\text { Solve: }-2 x-4=x+5$$
4 step solution
Problem 138
Describe how to solve an absolute value inequality involving the symbol <. Give an example.
3 step solution
Problem 139
Will help you prepare for the material covered in the next section. $$\text { Solve: } \frac{x+3}{4}=\frac{x-2}{3}+\frac{1}{4}$$
5 step solution
Problem 139
Describe how to solve an absolute value inequality involving the symbol \(>.\) Give an example.
5 step solution
Problem 140
Use the Pythagorean Theorem and the square root property to solve Exercises \(140-143 .\) Express answers in simplified radical form. Then find a decimal approximation to the nearest tenth. A rectangular park is 6 miles long and 3 miles wide. How long is a pedestrian route that runs diagonally across the park?
5 step solution
Problem 140
Explain why \(|x|<-4\) has no solution.
3 step solution
Problem 141
Use the Pythagorean Theorem and the square root property to solve Exercises \(140-143 .\) Express answers in simplified radical form. Then find a decimal approximation to the nearest tenth. A rectangular park is 4 miles long and 2 miles wide. How long is a pedestrian route that runs diagonally across the park?
4 step solution
Problem 141
Describe the solution set of \(|x|>-4\).
3 step solution
Problem 142
Use the Pythagorean Theorem and the square root property to solve Exercises \(140-143 .\) Express answers in simplified radical form. Then find a decimal approximation to the nearest tenth. The base of a 30 -foot ladder is 10 feet from a building. If the ladder reaches the flat roof, how tall is the building?
4 step solution
Problem 142
Solve each inequality using a graphing utility. Graph each side separately. Then determine the values of x for which the graph for the left side lies above the graph for the right side. $$-3(x-6)>2 x-2$$
3 step solution
Problem 143
Use the Pythagorean Theorem and the square root property to solve Exercises \(140-143 .\) Express answers in simplified radical form. Then find a decimal approximation to the nearest tenth. A baseball diamond is actually a square with 90 -foot sides. What is the distance from home plate to second base?
5 step solution
Problem 143
Solve each inequality using a graphing utility. Graph each side separately. Then determine the values of x for which the graph for the left side lies above the graph for the right side. $$-2(x+4)>6 x+16$$
3 step solution
Problem 144
An isosceles right triangle has legs that are the same length and acute angles each measuring \(45^{\circ} .\) (GRAPH NOT COPY) a. Write an expression in terms of \(a\) that represents the length of the hypotenuse. b. Use your result from part (a) to write a sentence that describes the length of the hypotenuse of an isosceles right triangle in terms of the length of a leg.
3 step solution
Problem 145
The length of a rectangular sign is 3 feet longer than the width. If the sign's area is 54 square feet, find its length and width.
4 step solution
Problem 145
A bank offers two checking account plans. Plan A has a base service charge of \(\$ 4.00\) per month plus \(10 \not c\) per check. Plan B charges a base service charge of \(\$ 2.00\) per month plus \(15 \not c\) per check. a. Write models for the total monthly costs for each plan if \(x\) checks are written. b. Use a graphing utility to graph the models in the same \([0,50,10]\) by \([0,10,1]\) viewing rectangle. c. Use the graphs (and the intersection feature) to determine for what number of checks per month plan A will be better than plan B. d. Verify the result of part (c) algebraically by solving an inequality.
4 step solution
Problem 146
A rectangular parking lot has a length that is 3 yards greater than the width. The area of the parking lot is 180 square yards. Find the length and the width.
4 step solution
Problem 146
Determine whether each statement makes sense or does not make sense, and explain your reasoning. I prefer interval notation over set-builder notation because it takes less space to write solution sets.
3 step solution
Problem 147
Each side of a square is lengthened by 3 inches. The area of this new, larger square is 64 square inches. Find the length of a side of the original square.
3 step solution
Problem 147
Determine whether each statement makes sense or does not make sense, and explain your reasoning. I can check inequalities by substituting 0 for the variable: When 0 belongs to the solution set, I should obtain a true statement, and when 0 does not belong to the solution set, I should obtain a false statement.
3 step solution
Problem 148
Each side of a square is lengthened by 2 inches. The area of this new, larger square is 36 square inches. Find the length of a side of the original square.
3 step solution
Problem 148
Determine whether each statement makes sense or does not make sense, and explain your reasoning. In an inequality such as \(5 x+4<8 x-5,1\) can avoid division by a negative number depending on which side I collect the variable terms and on which side I collect the constant terms.
2 step solution
Problem 149
A pool measuring 10 meters by 20 meters is surrounded by a path of uniform width, as shown in the figure at the top of the next column. If the area of the pool and the path combined is 600 square meters, what is the width of the path?
4 step solution
Problem 149
Determine whether each statement makes sense or does not make sense, and explain your reasoning. I'll win the contest if I can complete the crossword puzzle in 20 minutes plus or minus 5 minutes, so my winning time, \(x\) is modeled by \(|x-20| \leq 5\).
3 step solution
Problem 150
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement . $$(-\infty,-1] \cap[-4, \infty)=[-4,-1]$$
3 step solution
Problem 151
A machine produces open boxes using square sheets of metal. The figure illustrates that the machine cuts equal sized squares measuring 2 inches on a side from the corners and then shapes the metal into an open box by turning up the sides. If each box must have a volume of 200 cubic inches, find the length and width of the open box.
4 step solution