Question

50 POINTS!! EASY!

If y varies directly with x with a constant of proportionality of –2, what is y when x is 8? What is x when y is –20?

Answer 1

9514 1404 393

Answer:

• y = -16
• x = 10

Explanation:

The direct proportion equation is ...

y = kx

where k is the constant of proportionality. Here, you're told k=-2, so the equation is ...

y = -2x

For x=8, the value of y is ...

y = -2(8) = -16 . . . . . do the multiplication

For y = -20, the value of x is ...

-20 = -2x

10 = x . . . . . . . . . divide both sides by -2

Answer 2

-16 & 40

Explanation:

When x = 8

y = -2 × 8

y = -16

When y = -20

x = -2 × -20

x = 40