Chapter 7
Thinking Mathematically · 298 exercises
Problem 19
Graph each linear inequality. \(y>-4\)
3 step solution
Problem 19
Solve each system by the substitution method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{l}2 x-y=-5 \\ x+5 y=14\end{array}\right.\)
5 step solution
Problem 19
Calculate the slope of the line passing through the given points. If the slope is undefined, so state. Then indicate whether the line rises, falls, is horizontal, or is vertical. \((5,1)\) and \((-2,1)\)
4 step solution
Problem 19
Plot the given point in a rectangular coordinate system. \((1.25,-3.25)\)
3 step solution
Problem 20
a. Create a scatter plot for the data in each table. b. Use the shape of the scatter plot to determine if the data are best modeled by a linear function, an exponential function, a logarithmic function, or a quadratic function. $$ \begin{array}{|c|r|} \hline \boldsymbol{x} & \boldsymbol{y} \\ \hline 0 & -4 \\ \hline 1 & -1 \\ \hline 2 & 0 \\ \hline 3 & -1 \\ \hline 4 & -4 \\ \hline \end{array} $$
4 step solution
Problem 20
What is an objective function in a linear programming problem?
2 step solution
Problem 20
Graph each linear inequality. \(y>-2\)
3 step solution
Problem 20
Solve each system by the substitution method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{r}2 x+3 y=11 \\ x-4 y=0\end{array}\right.\)
6 step solution
Problem 20
Calculate the slope of the line passing through the given points. If the slope is undefined, so state. Then indicate whether the line rises, falls, is horizontal, or is vertical. \((-2,3)\) and \((1,3)\)
4 step solution
Problem 20
Plot the given point in a rectangular coordinate system. \((2.25,-4.25)\)
4 step solution
Problem 21
a. Create a scatter plot for the data in each table. b. Use the shape of the scatter plot to determine if the data are best modeled by a linear function, an exponential function, a logarithmic function, or a quadratic function. $$ \begin{array}{|c|c|} \hline \boldsymbol{x} & \boldsymbol{y} \\ \hline 0 & -3 \\ \hline 1 & -2 \\ \hline 2 & 0 \\ \hline 3 & 4 \\ \hline 4 & 12 \\ \hline \end{array} $$
3 step solution
Problem 21
What is a constraint in a linear programming problem? How is a constraint represented?
3 step solution
Problem 21
Graph each linear inequality. \(y \geq 0\)
3 step solution
Problem 21
Solve each system by the substitution method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{l}2 x-y=3 \\ 5 x-2 y=10\end{array}\right.\)
4 step solution
Problem 21
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=x^{2}-2\)
4 step solution
Problem 22
a. Create a scatter plot for the data in each table. b. Use the shape of the scatter plot to determine if the data are best modeled by a linear function, an exponential function, a logarithmic function, or a quadratic function. $$ \begin{array}{|c|r|} \hline \boldsymbol{x} & \boldsymbol{y} \\ \hline 0 & 4 \\ \hline 1 & 5 \\ \hline 2 & 7 \\ \hline 3 & 11 \\ \hline 4 & 19 \\ \hline \end{array} $$
3 step solution
Problem 22
In your own words, describe how to solve a linear programming problem.
5 step solution
Problem 22
Graph each linear inequality. \(x>0\)
3 step solution
Problem 22
Solve each system by the substitution method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{r}-x+3 y=10 \\ 2 x+8 y=-6\end{array}\right.\)
5 step solution
Problem 22
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=x^{2}+2\)
5 step solution
Problem 23
In Exercises 23-24, use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). Based on your graph, describe the shape of a scatter plot that can be modeled by \(f(x)=b^{x}, 0
3 step solution
Problem 23
Describe a situation in your life in which you would like to maximize something, but you are limited by at least two constraints. Can linear programming be used in this situation? Explain your answer.
4 step solution
Problem 23
In Exercises 23-38, graph the solution set of each system of inequalities. \(\left\\{\begin{array}{l}3 x+6 y \leq 6 \\ 2 x+y \leq 8\end{array}\right.\)
3 step solution
Problem 23
Solve each system by the substitution method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{rr}x+8 y= & 6 \\ 2 x+4 y= & -3\end{array}\right.\)
4 step solution
Problem 23
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=x-2\)
3 step solution
Problem 24
Use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). Based on your graph, describe the shape of a scatter plot that can be modeled by \(f(x)=b^{x}, 0
4 step solution
Problem 24
Graph the solution set of each system of inequalities. \(\left\\{\begin{array}{l}x-y \geq 4 \\ x+y \leq 6\end{array}\right.\)
3 step solution
Problem 24
Solve each system by the substitution method. Be sure to check all proposed solutions. \(\left\\{\begin{aligned}-4 x+y &=-11 \\ 2 x-3 y &=5 \end{aligned}\right.\)
6 step solution
Problem 24
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=x+2\)
3 step solution
Problem 25
Graph the solution set of each system of inequalities. \(\left\\{\begin{array}{r}2 x+y<3 \\ x-y>2\end{array}\right.\)
5 step solution
Problem 25
In Exercises 25-36, solve each system by the addition method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{l}x+y=1 \\ x-y=3\end{array}\right.\)
5 step solution
Problem 25
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=2 x+1\)
4 step solution
Problem 26
Use the directions for Exercises 7-8 to graph each logarithmic function. Based on your graph, describe the shape of a scatter plot that can be modeled by \(f(x)=\log _{b} x, 0
3 step solution
Problem 26
Graph the solution set of each system of inequalities. \(\left\\{\begin{array}{c}x+y<4 \\ 4 x-2 y<6\end{array}\right.\)
3 step solution
Problem 26
Solve each system by the addition method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{l}x+y=6 \\ x-y=-2\end{array}\right.\)
4 step solution
Problem 26
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=2 x-4\)
3 step solution
Problem 27
In Exercises 27-28, use the directions for Exercises 9-14 to graph each quadratic function. Use the quadratic formula to find \(x\)-intercepts, rounded to the nearest tenth. \(f(x)=-2 x^{2}+4 x+5\)
4 step solution
Problem 27
Graph the solution set of each system of inequalities. \(\left\\{\begin{array}{r}2 x+y<4 \\ x-y>4\end{array}\right.\)
3 step solution
Problem 27
Solve each system by the addition method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{l}2 x+3 y=6 \\ 2 x-3 y=6\end{array}\right.\)
5 step solution
Problem 27
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=-\frac{1}{2} x\)
3 step solution
Problem 28
Use the directions for Exercises 9-14 to graph each quadratic function. Use the quadratic formula to find \(x\)-intercepts, rounded to the nearest tenth. \(f(x)=-3 x^{2}+6 x-2\)
3 step solution
Problem 28
Graph the solution set of each system of inequalities. \(\left\\{\begin{array}{r}2 x-y<3 \\ x+y<6\end{array}\right.\)
3 step solution
Problem 28
Solve each system by the addition method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{l}3 x+2 y=14 \\ 3 x-2 y=10\end{array}\right.\)
6 step solution
Problem 28
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=-\frac{1}{2} x+2\)
4 step solution
Problem 29
In Exercises 29-30, find the vertex for the parabola whose equation is given by writing the equation in the form \(y=a x^{2}+b x+c\).\ \(y=(x-3)^{2}+2\)
2 step solution
Problem 29
Group members should choose a particular field of interest. Research how linear programming is used to solve problems in that field. If possible, investigate the solution of a specific practical problem. Present a report on your findings, including the contributions of George Dantzig, Narendra Karmarkar, and L. G. Khachion to linear programming.
5 step solution
Problem 29
Graph the solution set of each system of inequalities. \(\left\\{\begin{array}{l}x \geq 2 \\ y \leq 3\end{array}\right.\)
4 step solution
Problem 29
Solve each system by the addition method. Be sure to check all proposed solutions. \(\left\\{\begin{array}{r}x+2 y=2 \\ -4 x+3 y=25\end{array}\right.\)
5 step solution
Problem 29
Graph each equation in Exercises 21-32. Select integers for \(x\) from \(-3\) to 3 , inclusive. \(y=x^{3}\)
3 step solution
Problem 30
In Exercises 29-30, find the vertex for the parabola whose equation is given by writing the equation in the form \(y=a x^{2}+b x+c\).\ \(y=(x-4)^{2}+3\)
2 step solution