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.

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.