Question

The function f(x) varies directly with x, and f(x)=12 when x=8

which answer is the direct linear equation?

a) f(x)=8x

b) f(x)=12x


c) f(x)=2/3x

d) f(x)=3/2x

Answer 1

The answer would be d.

You can solve this by changing it up a little, such as changing it to f • x = 12
you can then divide by 8, because x = 8.
You're then left with f = 12/8 or 3/2
multiply by x again on both sides, and voila, f(x)=3/2x