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anonymous
 one year ago
If f(x) varies directly with x2, and f(x) = 75 when x = 5, find the value of f(4).
A.
100
B.
50
C.
48
D.
25
anonymous
 one year ago
If f(x) varies directly with x2, and f(x) = 75 when x = 5, find the value of f(4). A. 100 B. 50 C. 48 D. 25

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Remember that y is equal to f(x). f(x) = k*x^2 75 = k*(5)^2 75 = k*25 75/25 = k 3 = k k = 3

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Now, the equation f(x) = k*x^2 is turned into f(x) = 3x^2.

DecentNabeel
 one year ago
Best ResponseYou've already chosen the best response.1f(x)=k×x2 f(5)=75=k×52 75=25k find k=3 and so f(x)=3×x2 then f(4)=3×42=3×16

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Plug in x=4 to the equation f(x) = 3x^2, and you'll get the answer.

DecentNabeel
 one year ago
Best ResponseYou've already chosen the best response.1answer is option C
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