if y=12 when x=18, find x when y=-16

Question

direct variation equation that relate x and y for algebra 1.

Answer 1

y = 12 when x = 18

Direct variation equation is y = kx.

The given numbers form one ratio expressed as y/x = 12/18

To find x, when y = -16

we set up another ratio -16/x

By the definition both ratios are equal 12/18 = -16/x

Divide each side by negitive 16.

(12/18)/-16 = (-16/-16x)

0.66/-16 = x

 -0.04125 = x

x = -0.04125

 

Comments

The value of x  = -24.

Answer 2

y = 12 when x = 18

Direct variation equation is y = kx.

The given numbers form one ratio expressed as y/x = 12/18

To find x, when y = -16

we set up another ratio -16/x

By the definition both ratios are equal 12/18 = -16/x

Divide each side by negitive 16.

(12/18)/-16 = (-16/-16x)

1/-24 =1/x

x = - 24