91Ó°ÊÓ

Suppose yvaries directly as x. Write a direct variation equation that relates x and y. Then solve.

If$y=6$ when $x=9$, find x when $y=12$.

Solve each equation for y.

$5x−2y=12$

Solve each equation for y.

$3x+4y=10$

Graph each equation.

$2x−3y=6$

Suppose yvaries directly as x. Write a direct variation equation that relates x and y. Then solve.

When $y=−8$, $x=8$. What is x when $y=−6$?

A hot air balloon was at a height of 60 feet above the ground when it began to ascend. The balloon climbed at a rate of 15 feet per minute.

a. Make a table that shows the height of the hot air balloon after climbing for 1, 2, 3, and 4 minutes.

b. Let t represent the time in minutes since the balloon began climbing. Write an algebraic equation for a sequence that can be used to find the height h, of the balloon after tminutes.

c. Use your equation from part b to find the height, in feet, of the hot air balloon after climbing for 8 minutes.

The function $y=−15+3x$ represents the outside temperature, in degrees Fahrenheit, in a small Alaskan town where x represents the number of hours after midnight. The function is accurate for x values representing midnight through 4:00 PM. Find the zero of this function.

A 0

B 3

C 5

D$−15$

Suppose yvaries directly as x. Write a direct variation equation that relates x and y. Then solve

If $y=−5$when $x=−2$, what is y when$x=14$?

Solve each equation for y.

$3−\frac{1}{2}y=5x$

Find the rate of change represented in the table.