Question

Evaulate f(x)= 2x^2+3x+5 at f(x^2+x)

Answer 1

This is what I did:

Answer 2

(2x+x)(2x+x)
4x^2+2x^2+2x^2+9x^2+3x^2+3x^2+x^2

Answer 3

:S

Answer 4

you're on the right track, just a few algebraic mistakes

Answer 5

2x^2

plugging in "(x^2+x)" for x gives us

2(x^2 + x)^2

= 2(x^2+x)(x^2+x)

Answer 6

let's leave the 2 in front alone for now.

(x^2+x)(x^2+x)

F x^2 * x^2
O x^2 * x
I x * x^2
L x * x

Answer 7

try adding those up and combining like terms

Answer 8

x^4+x^2+x^2+x?

Answer 9

be careful with exponents

x^2 * x = x^3 not x^2
x * x = x^2

Answer 10

x^4+x^2+x^3+x^2

Answer 11

very close

the outer and inner products are the same

so x^4+x^3+x^3+x^2

Answer 12

or, to simplify, x^4+2x^3+x^2

Answer 13

anyway that's the hardest part, it's easy from there on out

the 3x term becomes 3(x^2+x) which is just 3x^2 + 3x

then tack on the + 5 at the very end

Answer 14

ah, almost forgot, we had a 2 at the beginning of the binomial expansion

so x^4+2x^3+x^2 becomes 2x^4 + 4x^3 + 2x^2

Answer 15

giving us 2x^4 + 4x^3 + 2x^2 + 3x^2 + 3x + 5

you can combine the x^2 terms as well