Chapter 1

Algebra for College Students · 399 exercises

Problem 20

Solve each compound inequality. Graph the solution set, and write it using interval notation. $$ x<5 \text { and } x>0 $$

5 step solution

Problem 20

Translate each verbal sentence into an equation, using \(x\) as the variable. Then solve the equation. $$ \text { When } 75 \% \text { of a number is added to } 6 \text { , the result is } 3 \text { more than the number. Find the number. } $$

3 step solution

Problem 21

Solve each formula for the specified variable. $$\begin{aligned}&A=P(1+r t) \text { for } t\\\&\text { (future value for simple interest) }\end{aligned}$$

4 step solution

Problem 21

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(5 x+2=3 x-6\)

5 step solution

Problem 21

Solve each equation. $$ |0.5 x|=6 $$

4 step solution

Problem 21

Solve each inequality. Graph the solution set, and write it using interval notation. \(-1.3 x \geq-5.2\)

3 step solution

Problem 21

Solve each compound inequality. Graph the solution set, and write it using interval notation. $$ x \leq 2 \text { and } x \leq 5 $$

4 step solution

Problem 21

Determine whether each is an expression or an equation. Simplify any expressions, and solve any equations. $$ 5(x+3)-8(2 x-6) $$

3 step solution

Problem 21

Two steamers leave a port on a river at the same time, traveling in opposite directions. Each is traveling \(22 \mathrm{mph}\). How long will it take for them to be \(110 \mathrm{mi}\) apart?

3 step solution

Problem 22

Solve each formula for the specified variable.$$\begin{aligned}&M=C(1+r) \text { for } r\\\&\text { (markup) }\end{aligned}$$

4 step solution

Problem 22

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(9 x+1=7 x-9\)

4 step solution

Problem 22

Solve each inequality. Graph the solution set, and write it using interval notation. \(-2.5 x \leq-1.25\)

5 step solution

Problem 22

Solve each equation. $$ |0.3 x|=9 $$

5 step solution

Problem 22

Solve each compound inequality. Graph the solution set, and write it using interval notation. $$ x \geq 3 \text { and } x \geq 6 $$

5 step solution

Problem 22

A train leaves Kansas City, Kansas, and travels north at \(85 \mathrm{~km}\) per \(\mathrm{hr}\). Another train leaves at the same time and travels south at \(95 \mathrm{~km}\) per hr. How long will it take before they are \(315 \mathrm{~km}\) apart?

6 step solution

Problem 23

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(7 x-5 x+15=x+8\)

5 step solution

Problem 23

Solve each inequality. Graph the solution set, and write it using interval notation. \(5 x+2 \leq-48\)

6 step solution

Problem 23

Solve each equation. $$ \left|\frac{1}{2} x+3\right|=2 $$

4 step solution

Problem 23

Determine whether each is an expression or an equation. Simplify any expressions, and solve any equations. $$ 5(x+3)-8(2 x-6)=12 $$

5 step solution

Problem 23

Mulder and Scully are driving to Georgia to investigate "Big Blue," a giant reptile reported in one of the local lakes. Mulder leaves the office at 8: 30 A.M. averaging 65 mph. Scully leaves at 9: 00 A.M., following the same path and averaging \(68 \mathrm{mph}\). At what time will Scully catch up with Mulder?

5 step solution

Problem 24

The formula \(F=\frac{9}{5} C+32\) can be solved for \(C\) to obtain \(C=\frac{5}{9}(F-32)\). Which one of the following is not equivalent to this? A. \(C=\frac{5}{9} F-\frac{160}{9}\) B. \(C=\frac{5 F}{9}-\frac{160}{9}\) C. \(C=\frac{5 F-160}{9}\) D. \(C=\frac{5}{9} F-32\)

4 step solution

Problem 24

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(2 x+4-x=4 x-5\)

6 step solution

Problem 24

Solve each inequality. Graph the solution set, and write it using interval notation. \(-2.5 x \leq-1.25\)

4 step solution

Problem 24

Solve each equation. $$ \left|\frac{2}{3} x-1\right|=5 $$

5 step solution

Problem 24

Determine whether each is an expression or an equation. Simplify any expressions, and solve any equations. $$ -7(x+4)+13(x-6)=18 $$

5 step solution

Problem 25

Solve each equation for \(y\). $$4 x+y=1$$

2 step solution

Problem 25

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(12 w+15 w-9+5=-3 w+5-9\)

8 step solution

Problem 25

Solve each equation. $$ \left|1+\frac{3}{4} x\right|=7 $$

4 step solution

Problem 25

Solve each compound inequality. Graph the solution set, and write it using interval notation. $$ x-3 \leq 6 \text { and } x+2 \geq 7 $$

5 step solution

Problem 25

Determine whether each is an expression or an equation. Simplify any expressions, and solve any equations. $$ \frac{1}{2} x-\frac{1}{6} x+\frac{3}{2}-8 $$

4 step solution

Problem 26

Solve each equation for \(y\). $$3 x+y=9$$

2 step solution

Problem 26

Solve each inequality. Graph the solution set, and write it using interval notation. \(\frac{5 x-6}{8}<8\)

5 step solution

Problem 26

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(-4 x+5 x-8+4=6 x-4\)

7 step solution

Problem 26

Solve each equation. $$ \left|2-\frac{5}{2} x\right|=14 $$

4 step solution

Problem 26

Determine whether each is an expression or an equation. Simplify any expressions, and solve any equations. $$ \frac{1}{3} x+\frac{1}{5} x-\frac{1}{2}+7 $$

6 step solution

Problem 26

Sharon commutes to her office by train. When she walks to the train station, it takes her 40 min. When she rides her bike, it takes her 12 min. Her average walking rate is 7 mph less than her average biking rate. Find the distance from her house to the train station. $$ \begin{array}{|l|l|l|l|} \hline & \text { Rate } & \text { Time } & \text { Distance } \\ \text { Walking } & & & \\ \text { Biking } & & & \\ \hline \end{array} $$

6 step solution

Problem 27

Solve each equation for \(y\). $$x-2 y=-6$$

3 step solution

Problem 27

Solve each inequality. Graph the solution set, and write it using interval notation. \(\frac{2 x-5}{-4}>5\)

6 step solution

Problem 27

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(3(2 t-4)=20-2 t\)

6 step solution

Problem 27

Solve each equation. $$ |0.02 x-1|=2.50 $$

5 step solution

Problem 27

Complete the six problem-solving steps to solve each problem. In 2015 , the corporations securing the most U.S. patents were IBM and Samsung. Together, the two corporations secured a total of 12,368 patents, with Samsung receiving 2250 fewer patents than IBM. How many patents did each corporation secure? (Data from U.S. Patent and Trademark Office.) Step 1 Read the problem carefully. We are asked to find ______ . 2 Assign a variable. Let \(x=\) the number of patents that IBM secured. Step Then \(x-2250=\) the number of ______ . Step 3 Write an equation. ____\(+ _____ \ldots=12,368\) Step 4 Solve the equation. \(x=\) ______ . \(\begin{array}{llll}\text { Step } 5 & \text { State the answer. } & \text { IBM secured } & \text { patents. Samsung secured } & \text { patents. }\end{array}\) Step 6 Check. The number of Samsung patents was _____ fewer than the number of _____ The total number of patents was \(7309+\) _____ \(= ______\).

6 step solution

Problem 27

Solve each compound inequality. Graph the solution set, and write it using interval notation. $$ -3 x>3 \text { and } x+3>0 $$

5 step solution

Problem 27

Johnny leaves Memphis to visit his cousin Anne, who lives in the town of Hornsby, Tennessee, 80 mi away. He travels at an average rate of 50 mph. One- half hour later, Anne leaves to visit Johnny, traveling at an average rate of \(60 \mathrm{mph}\). How long after Anne leaves will it be before they meet?

4 step solution

Problem 28

Solve each equation for \(y\). $$x-5 y=-20$$

2 step solution

Problem 28

Solve each inequality. Graph the solution set, and write it using interval notation. \(\frac{3 x-2}{-5}<6\)

4 step solution

Problem 28

Solve each equation, and check the solution. If applicable, tell whether the equation is an identity or a contradiction. \(2(3-2 x)=x-4\)

6 step solution

Problem 28

Solve each equation. $$ |0.04 x-3|=5.96 $$

5 step solution

Problem 28

On an automobile trip, Laura maintained a steady rate for the first two hours. Rush-hour traffic slowed her rate by 25 mph for the last part of the trip. The entire trip, a distance of \(125 \mathrm{mi},\) took \(2 \frac{1}{2} \mathrm{hr} .\) What was her rate during the first part of the trip?

5 step solution

Problem 29

Solve each problem. The John Hancock Center in Chicago has a rectangular base. The length of the base measures \(65 \mathrm{ft}\) less than twice the width. The perimeter of the base is \(860 \mathrm{ft}\). What are the dimensions of the base?

6 step solution

Problem 29

Solve each equation for \(y\). $$4 x+9 y=11$$

2 step solution

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