Algbrea 2 Math

Question

x^2+8x+15=

Answer 1

is the question wanting you to factor?

the idea is that you want to find two terms that add together to be the middle term (8) and multiply together to be the end term (15). in this case 5 and 3 work for that because 5 + 3 = 8 and 5*3 = 15, meaning that the factored expression here is

(x + 5)(x + 3)

Answer 2

Hi David;

x²+8x+15=

We need to FOIL...

We know that...

FIRST must be (x)(x).

OUTER and INNER must add up to be 8x.

LAST must be (15)(1) or (1)(15) or (3)(5) or (5)(3) and that both numbers must be positive.

(x+5)(x+3)

FOIL...

FIRST..(x)(x)=x²

OUTER...(x)(3)=3x

INNER...(5)(x)=5x

LAST...(5)(3)=15

x²+3x+5x+15

x²+8x+15