# If F (x) =3x^2 +5x -2 Find F(-2) F(4), Can You Help?

If you have a statement,

F(x) = 3X^2 + 5X - 2 it is telling you that this is the function for all values of X

so when you are asked to find F(-2) or F(4), you are being asked to substitute the values for X in the function.

So F(-2) = 3(-2)^2 + 5(-2) - 2 ..... You then solve for the answer

Repeat the process for F(4)

The answers you were given by 'Chuckfoor' are correct, I just thought you may want the process on how he got it.

thanked the writer.
Anonymous commented
Thank you that helps but how do you actually come up with answer by factoring or simplyfying?
Anonymous commented
When you have substituted the value of X, you just work out the answer.
So ... F(-2) = 3(-2)^2 + 5(-2) - 2

F(-2) = (3)(4) + (-10) - 2
F(-2) = 12 -10 -2
F(-2) = 0

F(4) = 3(4^2) + 5(4) - 2
F(4) = 3(16) + 20 - 2
F(4) = 48 + 20 - 2
F(4) = 66
Anonymous commented
Oooooops I earlier said the answers given by Chuckfoor were correct!

The answers are actually F(-2) = 0 and F(4) = 66
F(x) = 3x2 + 5x - 2 = (3x - 1)(x + 2)

F(-2) = (3(-2) - 1)((-2)+2) = (-6-1)(0) = 0
F(4) = (3(4) - 1)((4) + 2) = (12-1)(6) = 11*6 = 66

A reasonable way to compute this using computer code or a calculator is this.
F(x) = (3x + 5)x - 2
At each step, you perform a multiplication (by x) and an addition (by a constant).

F(-2) = (3(-2)+5)(-2) - 2 = (-6+5)(-2) - 2 = -1*-2 - 2 = 2 - 2 = 0
F(4) = (3(4)+5)(4) - 2 = (12+5)(4) - 2 = 17*4 - 2 = 68 - 2 = 66

thanked the writer.
Anonymous commented
Hey i have been so busy with school and the girls i haven't had time to tie my shoe. I just wanted to thank you but i don't think there is much help for me. I appreciate your help with math though. I wish i had your brain. Iyou said you wanted my grade i got a d in my ip's . I tried my best and got help on some and still recieved an D. I guess it is better than an F but itreally shoots your hopes down when you get a grade like that and you really worked hard to get a good one. Well any way thanks for everything later annastar1
H(-1)= (2(-1) + 1)³
thanked the writer.
For F(-2) that should be 0, for F(4) it should be 52. Good luck
thanked the writer.
Anonymous commented
I believe F(4) = 66