Chapter 9

Write the quadratic equation in standard form. Solve using the quadratic formula. $$16=-x^{2}+11 x$$

Use a graphing calculator to approximate the solution of the equation. $$ x^{2}+6 x-7=0 $$

Graph the equation. $$2 x-4 y=24$$

Simplify the expression. $$\sqrt{7} \cdot \frac{\sqrt{18}}{\sqrt{2}}$$

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=4 x^{2} $$

COMPUTER MODEMS In Exercises \(46-48\), use the following data which list the prices of several computer modems.\$ 230, \$ 220, \$ 170, \$ 215, \$ 190, \$ 200, \$ 200, \$ 150, \$ 170 Use a stem-and-leaf plot to order the data from least to greatest.

Use a calculator to evaluate the expression. Round the results to the nearest hundredth. $$\frac{2 \pm 5 \sqrt{3}}{5}$$

Write an equation of the line that passes through the two points. $$(3,-2),(5,4)$$

Write the quadratic equation in standard form. Solve using the quadratic formula. $$5 x-1=-6 x^{2}$$

Use a graphing calculator to approximate the solution of the equation. $$ 5 x^{2}+5 x-1=0 $$

Graph the equation. $$y=x^{2}+x+2$$

Simplify the expression. $$-\sqrt{4} \cdot \frac{\sqrt{81}}{\sqrt{36}}$$

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=x^{2}+4 x-1 $$

Use a calculator to evaluate the expression. Round the results to the nearest hundredth. $$\frac{1 \pm 6 \sqrt{8}}{6}$$

Write an equation of the line that passes through the two points. $$(-3,-9),(5,7)$$

Write the quadratic equation in standard form. Solve using the quadratic formula. $$2 q^{2}-6=-4 q$$

Use a graphing calculator to approximate the solution of the equation. $$ -8 x^{2}-24 x+32=0 $$

Graph the equation. $$y=-x^{2}+4 x+1$$

Simplify the expression. $$\frac{\sqrt{10} \cdot \sqrt{16}}{\sqrt{5}}$$

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=-3 x^{2}+6 x-9 $$

Use a calculator to evaluate the expression. Round the results to the nearest hundredth. $$\frac{7 \pm 3 \sqrt{2}}{-1}$$

Write an equation of the line that passes through the two points. $$(2,3),(-4,6)$$

Write the quadratic equation in standard form. Solve using the quadratic formula. $$5 z-2 z^{2}+15=8$$

Use a graphing calculator to approximate the solution of the equation. $$ \frac{1}{2} x^{2}+2 x-16=0 $$

Graph the equation. $$y=3 x^{2}-2 x+6$$

Simplify the expression. $$\frac{-2 \sqrt{20}}{\sqrt{100}}$$

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=4 x^{2}+8 x-3 $$

Use a calculator to evaluate the expression. Round the results to the nearest hundredth. $$\frac{2 \pm 5 \sqrt{6}}{2}$$

Write the quadratic equation in standard form. Solve using the quadratic formula. $$-1+3 x^{2}=2 x$$

Use a graphing calculator to approximate the solution of the equation. $$ \frac{5}{4} x^{2}+15 x+40=0 $$

The variables x and y vary directly. Use the given values to write an equation that relates x and y. $$x=6, y=42$$

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=2 x^{2}-x $$

Use a calculator to evaluate the expression. Round the results to the nearest hundredth. $$\frac{5 \pm 6 \sqrt{3}}{3}$$

Write the quadratic equation in standard form. Solve using the quadratic formula. $$-5 c^{2}+9 c=4$$

The variables x and y vary directly. Use the given values to write an equation that relates x and y. $$x=54, y=-9$$

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=6 x^{2}-4 x $$

Use a calculator to evaluate the expression. Round the results to the nearest hundredth. $$\frac{3 \pm 4 \sqrt{5}}{4}$$

Write the quadratic equation in standard form. Solve using the quadratic formula. $$-16 b=-8 b^{2}-8$$

The consumption of Swiss cheese in the United States from 1970 to 1996 can be modeled by \(P=-0.002 t^{2}+0.056 t+0.889\) where \(P\) is the number of pounds per person and \(t\) is the number of years since \(1970 .\) According to the graph of the model, in what year would the consumption of Swiss cheese drop to \(0 ?\) Is this a realistic prediction? (GRAPH CANNOT COPY).

The variables x and y vary directly. Use the given values to write an equation that relates x and y. $$x=7, y=5$$

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=3 x^{2}-2 x $$

Use a calculator to evaluate the expression. Round the results to the nearest hundredth. $$\frac{7 \pm 0.3 \sqrt{12}}{-6}$$

Find the x-intercepts of the graph of the equation. $$y=3 x^{2}-6 x-24$$

Use the following information. The number of recreational vehicles (RVs) sold in the United States from 1985 to 1991 can be modeled by \(N=-9.5 t^{2}+48.9 t+343.5,\) where \(N\) represents the number of vehicles sold (in thousands) and \(t\) represents the number of years since 1985. Sketch a graph of the model for positive values of \(x\) and \(y\).

The variables x and y vary directly. Use the given values to write an equation that relates x and y. $$x=-13, y=-52$$

Physicians can approximate the Body Surface Area of an adult (in square meters) using an index called \(B S A\) where \(H\) is height in centimeters and \(W\) is weight in kilograms. Body Surface Area: \(\sqrt{\frac{H W}{3600}}\) Find the \(B S A\) of a person who is 180 centimeters tall and weighs 75 kilograms.

SKETCHING GRAPHS Sketch the graph of the function. Label the vertex. $$ y=x^{2}+x+4 $$

Solve the equation or write no solution. Write the solutions as integers if possible. Otherwise write them as radical expressions. $$x^{2}=36$$

Find the x-intercepts of the graph of the equation. $$y=2 x^{2}-6 x-8$$

The variables x and y vary directly. Use the given values to write an equation that relates x and y. $$x=\frac{3}{4}, y=3$$