Expert: Richard J. Raridon - 6/28/2006

Question
Hi mr rairdon can you show me how to work these two problems out please, these problems needs to be factored completely if you could show me the steps it makes it alot easier for me to understand the problem thanks in advance

1.7x^2-65x+18=0

2.125x^3+512

Answer
1. the factors are going to be of the form (ax+b)(cx+d)
where you know that ac = 7 and bd = 18
so obviously, a or c = 7 and the other = 1
b and d have to be factors of 18 and they have to be negative so you have (-1,-18),(-2,-9) and (-3,-6).  Try some different combinations and you'll come up with
(7x-2)(x-9)
2. you can't factor 125x^3+512.
If you had 125x^3-512, that would factor to
(5x-8)(25x^2+40x+64)