The f(x)varies directly with x, and f(x)=8 when x=6

2 answers

Which answer is the direct linear variation equation?

F (x) = 3/4x
F (x)= 8 my choice
F (×)=6x
F (×)= 4/3×
no, you picked a constant function. It is always 8.

Direct variation means that y = kx
for some constant k.
Since y(6)=8,
8 = k*6
k = 8/6 = 4/3

hence, f(x) = 4/3 x
choice D