Question

F(x)= x^2-4x+5
F(1)=
F(-1)=
F(2)=

Answer 1

just plug in the values in the parenthesis instead of x, and evaluate.

Answer 2

Thats what i tried doing. For f(1) i got 2 for f(-1) i got 8, but 8 isnt any of my answer choices.

Answer 3

First one:
(1)^2-4*(1)+5 and just do the same thing for everything else.

Answer 4

(-1)^2-(4)(-1)+5=1+4+5=10

Answer 5

You got f(1) correct.
For f(-1), you probably made a mistake squaring -1
(-1)^2 = (-1)(-1) = 1

Answer 6

So for f(2) is that 1?

Answer 7

Yes =) Good work.

Answer 8

;) so what about f(a) and f(a+1) ?

Answer 9

Plug in a and see what you get. Or plug in (a+1) and see what you get.
You won't be able to get a single number like before, which is okay.

Answer 10

So, a^2-4a+5 ?

Answer 11

Good.
Now, when you plug in (a+1) remember to put parenthesis around it.

Answer 12

do i add the 1 to anything from (a+1) ?

Answer 13

Plug in (a+1), and then simplify. Let me see your "plug it in" step.

Answer 14

(a+1)^2-4(a+1)+5 ?

Answer 15

Perfect. Okay, now you just have to be careful that you simplify correctly =)
There are two little tricks to doing that. The first is to remember to distribute the -4.
The second is that (a+1)^2 mean (a+1) times itself, so (a+1)(a+1)

Answer 16

Let me see you try to simplify.

Answer 17

Um, a^2-2a+15?

Answer 18

hmmm I'd need to see your middle steps. The 15 is kind of baffling me.

Answer 19

Just put the value x in each case & solve ur prob:)