Question

Select one of the factors of x^3 + 4x2 + 9x + 36
a. none of the above
b.(x^2 + 4)
c.(x^2 + 9)
d.(x + 9)

Answer 1

This factors to : (x+4)(x^2+9), so C

Answer 2

how did you do that? can you please explain

Answer 3

yeah no problem

Answer 4

factor the first two terms

x^3 + 4x2 = x^2(x + 4)

Can you factor the second two terms?

9x + 36 = ???

Answer 5

yeah is 4

Answer 6

we can factor by grouping:
x^3 + 4x2 + 9x + 36
(x^3+4x^2)+(9x+36)
x^2(x+4)+9(x+4)
(x^2+9)(x+4)

Answer 7

4?

or 9(x + 4)

Answer 8

any questions?

Answer 9

how did the 9 come before the 4? (x^2+9)(x+4)

Answer 10

well since we grouped this up into:
(x^3+4x^2)+(9x+36)
we had to factor each one of there terms:
For (x^3+4x^2) we factored a x^2 giving us: x^2(x+4)
For (9x+36) we factored a 9 giving us: 9(x+4)

Answer 11

ok thank you ! :)