Determine whether y varies directly with x. If so, find the constant of variation k.

3y = –7x – 18

Find the value of y for a given value of x, if y varies directly with x.

If y = 2.52 when x = 8.4, what is y when x = 2.7?

A. 9

B. –9

C. 0.81

D. –0.81

### 2 Answers

3y = –7x – 18

y does not vary directly with x

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y varies directly with x.

y = kx , where k is any constant

y=2.52 when x=8.4

2.52 = k(8.4)

k = 2.52/8.4 =0.3

y=0.3x

when x=2.7

y=(0.3)(2.7) = 0.81

-6y=-5x