[MOVED] Function evaluation: f(x) = -x^2 + 4

[kjones]

Can you tell me if I'm on the right track on the following 4 questions?

The function is f(x) = -x^2 + 4.

Find and simplify:

a) f(0) = (0)+ 4

b) f(3) = -(3)^2 + 4

c) f(-a) = -(-a)^2 +4
= -a2 +4

d) f(a-1) = -(a-1)^2 +4
= -(a-1) (a-1) + 4
= a^2 +1a - 1a +1
= a^2 + 2a^2 + 1

 

[askmemath]

Yup you on the right track

b) -9+4 = -5

d) f(a-1) = -(a-1)^2 +4
= -(a-1) (a-1) + 4
You were fine till here.
-(a^2 -2a +1) +4
-a^2 +2a - 1 +4
-a^2 +2a +3

 

[kjones]

One more question...

on C) f(-a) = -(-a)^2 + 4
= -a^2 +4

Is this simplified?

Thanks for your help!

K