Question

50 points if you can solve!!!!!!!!!!!!! ~URGENT~

The function f(x) varies directly with x and f(x)=3 when x=12.

What is the value of f(x) when x=40?
_____________________________________________________________________

A. 160

B. 4

C. 10

D. 480

Answer 1

I do this a little differently then most.....but if it varies directly, then I make a proportion......and f(x) is the same as y

3/12 = y/40
cross multiply
(12)(y) = (3)(40)
12y = 120
y = 120/12
y = 10 <===== so f(x) or y = 10