Question

if f(x)=(x+1)(1-x^2), evaluate f(a+3)

Answer 1

some help me

Answer 2

Plug in (a+3) for every value of x in f(x).

Answer 3

uh huh i got =((a+3)+1)(1-(a+3)^2) dont know what to do after that

Answer 4

\[f(a+3) = (a+3+1)(1-(a+3)^2)\]
just like pjschlotter said.

Answer 5

Got it!

Answer 6

Solve it like:
(a+3+1) = (a+4)
(a+4) (1-(a^2 +6a + 9))
(a+4) (-a^2 -6a -8)

Answer 7

You can also multiply (a+4) for the rest, but I don't think it's necessary... this form is clearer.

Answer 8

thank you where is the 6a from?

Answer 9

It's from the development of (a+3)^2, right?
(b+c)^2 = b^2 + 2.b.c + c^2
So,
(a+3)^2 = a^2 + 2.a.3 + 3^2 = a^2 + 6a + 3^2

Answer 10

ok kinda got it so if the number is 6 instead of 3 then it would be 12a instead of 6a correct?

Answer 11

Correct!

Answer 12

so is the solution -12a^2-32a-32

Answer 13

It's (a+4) (-a^2 -6a -8), as I said!

Answer 14

oh i though you have to combine them. but thanks alot how do i become a fan?

Answer 15

can you help me with another problem?

Answer 16

Of course, just send it. :)

Answer 17

Erm, actually, I gotta go sleep. lol Class tomorrow. See ya.