Chapter 7

Thinking Mathematically · 298 exercises

Problem 1

In Exercises 1-6, use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). \(f(x)=4^{x}\)

3 step solution

Problem 1

In Exercises 1-22, graph each linear inequality. \(x+y \geq 2\)

4 step solution

Problem 1

In Exercises 1-4, determine whether the given ordered pair is a solution of the system. \((2,3)\) \(\left\\{\begin{array}{l}x+3 y=11 \\ x-5 y=-13\end{array}\right.\)

3 step solution

Problem 1

In Exercises \(1-8\), use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(x-y=3\)

3 step solution

Problem 1

In Exercises 1-20, plot the given point in a rectangular coordinate system. \((1,4)\)

4 step solution

Problem 2

Use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). \(f(x)=5^{x}\)

4 step solution

Problem 2

Graph each linear inequality. \(x-y \leq 1\)

3 step solution

Problem 2

Determine whether the given ordered pair is a solution of the system. \((-3,5)\) \(\left\\{\begin{array}{l}9 x+7 y=8 \\ 8 x-9 y=-69\end{array}\right.\)

4 step solution

Problem 2

Use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(x+y=4\)

3 step solution

Problem 2

Plot the given point in a rectangular coordinate system. \((2,5)\)

4 step solution

Problem 3

Use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). \(y=2^{x+1}\)

3 step solution

Problem 3

Graph each linear inequality. \(3 x-y \geq 6\)

3 step solution

Problem 3

Determine whether the given ordered pair is a solution of the system. \((2,5)\) \(\left\\{\begin{array}{r}2 x+3 y=17 \\ x+4 y=16\end{array}\right.\)

2 step solution

Problem 3

Use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(3 x-4 y=12\)

3 step solution

Problem 3

Plot the given point in a rectangular coordinate system. \((-2,3)\)

4 step solution

Problem 4

Use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). \(y=2^{x-1}\)

3 step solution

Problem 4

Graph each linear inequality. \(3 x+y \leq 3\)

3 step solution

Problem 4

Determine whether the given ordered pair is a solution of the system. \((8,5)\) \(\left\\{\begin{array}{l}5 x-4 y=20 \\ 3 y=2 x+1\end{array}\right.\)

2 step solution

Problem 4

Use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(2 x-5 y=10\)

3 step solution

Problem 4

Plot the given point in a rectangular coordinate system. \((-1,4)\)

3 step solution

Problem 5

Use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). \(f(x)=3^{x-1}\)

3 step solution

Problem 5

In Exercises 5-8, an objective function and a system of linear inequalities representing constraints are given. a. Graph the system of inequalities representing the constraints. b. Find the value of the objective function at each corner of the graphed region. c. Use the values in part (b) to determine the maximum value of the objective function and the values of \(x\) and \(y\) for which the maximum occurs. Objective Function $$ z=x+y $$ Constraints $$ \left\\{\begin{array}{l} x \leq 6 \\ y \geq 1 \\ 2 x-y \geq-1 \end{array}\right. $$

4 step solution

Problem 5

Graph each linear inequality. \(2 x+3 y>12\)

3 step solution

Problem 5

In Exercises 5-12, solve each system by graphing. Check the coordinates of the intersection point in both equations. \(\left\\{\begin{array}{l}x+y=6 \\ x-y=2\end{array}\right.\)

4 step solution

Problem 5

Use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(2 x+y=6\)

4 step solution

Problem 5

Plot the given point in a rectangular coordinate system. \((-3,-5)\)

3 step solution

Problem 6

Use a table of coordinates to graph each exponential function. Begin by selecting \(-2,-1,0,1\), and 2 for \(x\). \(f(x)=3^{x+1}\)

4 step solution

Problem 6

An objective function and a system of linear inequalities representing constraints are given. a. Graph the system of inequalities representing the constraints. b. Find the value of the objective function at each corner of the graphed region. c. Use the values in part (b) to determine the maximum value of the objective function and the values of \(x\) and \(y\) for which the maximum occurs. Objective Function $$ z=3 x-2 y $$ Constraints $$ \left\\{\begin{array}{l} x \geq 1 \\ x \leq 5 \\ y \geq 2 \\ x-y \geq-3 \end{array}\right. $$

4 step solution

Problem 6

Graph each linear inequality. \(2 x-5 y<10\)

3 step solution

Problem 6

Solve each system by graphing. Check the coordinates of the intersection point in both equations. \(\left\\{\begin{array}{l}x+y=2 \\ x-y=4\end{array}\right.\)

3 step solution

Problem 6

Use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(x+3 y=6\)

3 step solution

Problem 6

Plot the given point in a rectangular coordinate system. \((-4,-2)\)

4 step solution

Problem 7

In Exercises 7-8, a. Rewrite each equation in exponential form. b. Use a table of coordinates and the exponential form from part (a) to graph each logarithmic function. Begin by selecting \(-2,-1,0,1\), and 2 for \(y\). \(y=\log _{4} x\)

3 step solution

Problem 7

An objective function and a system of linear inequalities representing constraints are given. a. Graph the system of inequalities representing the constraints. b. Find the value of the objective function at each corner of the graphed region. c. Use the values in part (b) to determine the maximum value of the objective function and the values of \(x\) and \(y\) for which the maximum occurs. Objective Function $$ z=6 x+10 y $$ Constraints $$ \left\\{\begin{array}{l} x+y \leq 12 \\ x+2 y \leq 20 \\ x \geq 0 \\ y \geq 0 \end{array}\right\\} \begin{aligned} &\text { Quadrant I and } \\ &\text { its boundary } \end{aligned} $$

4 step solution

Problem 7

Graph each linear inequality. \(5 x+3 y \leq-15\)

3 step solution

Problem 7

Solve each system by graphing. Check the coordinates of the intersection point in both equations. \(\left\\{\begin{array}{l}2 x-3 y=6 \\ 4 x+3 y=12\end{array}\right.\)

4 step solution

Problem 7

Use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(5 x=3 y-15\)

3 step solution

Problem 7

Plot the given point in a rectangular coordinate system. \((4,-1)\)

4 step solution

Problem 8

a. Rewrite each equation in exponential form. b. Use a table of coordinates and the exponential form from part (a) to graph each logarithmic function. Begin by selecting \(-2,-1,0,1\), and 2 for \(y\). \(y=\log _{5} x\)

3 step solution

Problem 8

An objective function and a system of linear inequalities representing constraints are given. a. Graph the system of inequalities representing the constraints. b. Find the value of the objective function at each corner of the graphed region. c. Use the values in part (b) to determine the maximum value of the objective function and the values of \(x\) and \(y\) for which the maximum occurs. Objective Function $$ z=x+3 y $$ Constraints $$ \left\\{\begin{array}{l} x+y \geq 2 \\ x \leq 6 \\ y \leq 5 \\ x \geq 0 \\ y \geq 0 \end{array}\right\\} \text { Quadrant I and } $$

4 step solution

Problem 8

Graph each linear inequality. \(3 x+4 y \leq-12\)

4 step solution

Problem 8

Solve each system by graphing. Check the coordinates of the intersection point in both equations. \(\left\\{\begin{array}{l}4 x+y=4 \\ 3 x-y=3\end{array}\right.\)

3 step solution

Problem 8

Use the \(x\) - and \(y\)-intercepts to graph each linear equation. \(3 x=2 y+6\)

3 step solution

Problem 8

Plot the given point in a rectangular coordinate system. \((2-2)\)

3 step solution

Problem 9

In Exercises 9-14, a. Determine if the parabola whose equation is given opens upward or downward. b. Find the vertex. c. Find the \(x\)-intercepts. d. Find the y-intercept. e. Use (a)-(d) to graph the quadratic function. \(y=x^{2}+8 x+7\)

5 step solution

Problem 9

Use the directions for Exercises 5-8 to solve Exercises 9-12. Objective Function $$ z=5 x-2 y $$ Constraints $$ \left\\{\begin{array}{l} 0 \leq x \leq 5 \\ 0 \leq y \leq 3 \\ x+y \geq 2 \end{array}\right. $$

4 step solution

Problem 9

Graph each linear inequality. \(2 y-3 x>6\)

3 step solution

Problem 9

Solve each system by graphing. Check the coordinates of the intersection point in both equations. \(\left\\{\begin{array}{l}y=x+5 \\ y=-x+3\end{array}\right.\)

3 step solution

Problem 9

In Exercises 9-20, 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. \((2,6)\) and \((3,5)\)

3 step solution

Problem 9

Plot the given point in a rectangular coordinate system. \((-4,0)\)

3 step solution

Show/ page