Question

Factor completely:
x^2+9x+18
I know my answer will be written in the form (x +or- ...) (x +or- ...) and i know i have to find what multiplies to be 18 and adds to be 9, but this is where I get stuck. I can't for the life of me think of what the heck would multiply to be 18 and add to be 9. 3 and 4, 9 and 2, and 18 and 1 wont work and I cant use negative numbers since it's all positive right?
am i missing it completely? Is it super obvious or does it even have one i can use? Is it no solution? argh...

Answer 1

Factors of 18:

9*2 = 18
6*3 =18
18*1 = 18


Now add them and see which are equal to 9.

9+2=
6+3=
18+1=

Answer 2

And remember that, \[\huge 3\times4\neq 18\]

Answer 3

oh wow i ..... completely forgot 6x3... good going me wow that was dumb

Answer 4

:)

Answer 5

thank you lmao

Answer 6

No problem!