Question

Help? Will fan and give medal for right answer!!

If f(x) varies directly with x^2, and f(x) = 75 when x = 5, find the value of f(4)

Answer 1

So f(x) is like y.
So ur equation can be written as y=x^2 (k). Where k is a constant which u have to find.

So find k when y=75 and x=5
75=5^2 (k)

Can you solve for k?

Answer 2

25? @nikato

Answer 3

No.
75=25k. Divide both side by 25. So what's k?

Answer 4

3 @nikato

Answer 5

3=1 @nikato

Answer 6

ok. so k=3
now ur equation is y=x^2(3)
and now ur solving for f(x) which means that x=4
plug 4 into x
and solve for y

y=4^2(3)

Answer 7

24 @nikato

Answer 8

@nikato

Answer 9

now what is 4^2?

then multiply that by 3

Answer 10

16 x 3= 48 lol sorry i was doing 4x2 @nikato

Answer 11

no problem. 48 is correct