Question

Suppose y varies directly with x. Write a direct variation equation that relates x and y.

y= 7 1/2 when x=3

y=3/2x
y=2/3x*
y=5/2x
y=2/5x

Answer 1

Hmmm (2/3)*3 = 2, not 7

y/x = (7 1/2)/3 = (15/2)/3 = 15/6 = 5/2

y = 5/2 x

You need to learn to check your answers. At least do a sanity check. 2/3x < x, so how could y = 2/3 x relate 3 and 7?

Answer 2

Thank you Steve!