Factor: x2 - 11x + 18
a: (x + 1)(x - 12)
b: (x - 3)(x - 6)
c: (x - 2)(x - 9)
d: prime

Question

Factor: x2 - 11x + 18
 a: (x + 1)(x - 12)
 b: (x - 3)(x - 6)
 c: (x - 2)(x - 9)
 d: prime

usukidoll · Answer

now this time we need all combinations of 18
1 x 18 = 18
2 x 9 = 18
6 x 3 = 18

so out of all the combinations, which 2 numbers will give me 11 (the numbers are on the left side of the equation)

usukidoll · Answer

so what's 1 +18 ? 
2+9 ?
6+ 3 ?

anonymous · Answer

it's c

usukidoll · Answer

can you show me why it's c?

usukidoll · Answer

I want to make sure you understand the process of factorization

anonymous · Answer

Find the two factors of 18 that when added together equal 11: 

-9x-2=18 and -9+-2=-11, so the two factors are -9 and -2. 

(x-9) and (x-2) 

set the two equations to 0 and solve: 

x=9 and x=2.

usukidoll · Answer

wow that's good
(x-9)(x-2) = x^2-2x-9x+18 = x^2-11x+18

usukidoll · Answer

good job :)