SOLUTION: the function f(x) varies directly with x and f(x) = 24 when x = -4 what is f(x) when x = 12?

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Question 995229: the function f(x) varies directly with x and f(x) = 24 when x = -4 what is f(x) when x = 12?
Found 2 solutions by josgarithmetic, doffy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=kx and 24=k%28-4%29.
Find k and find f(12).

Answer by doffy(2) About Me  (Show Source):
You can put this solution on YOUR website!
Since f(x) is directly proportional to x, therfore,
f(x)=kx.
24 = k(-4),
k = -6.
Using the value of k and the given condition, we have:
f(x)= -6*12
f(x) = -72