Question

Factor.x ^2 + 17x + 72

Answer 1

so we need to factor it into (ax+b)(cx+d)
since we have 1x^2, a and c=1

so factor into (x+b)(x+d)
if we expand, we get

`(x+b)(x+d)=x^2+(b+d)x+bd`

so we need 2 numbers that add to get the middle number and multiply to get the last number


I would factor the last number and see which ones add to the middle one

what 2 numbers multily to get 72 and add to get 17?
hmm, list factor of 72 and add them
1+72=73, nope
2+36=38, nope
3+24=27, nope
4+13=17, yep


so it facotrs to (x+4)(x+13)

Answer 2

Find factors of x^2 and 72, that, when combined, will give you 17x

x ^2 + 17x + 72

x 9

x 8

(x + 9)(x + 8) is your factor.

hope this helps