SOLUTION: Hello, what are the steps to solving this math question: Factor completely: 9x^2 + 9x -28

Algebra.Com
Question 1149306: Hello, what are the steps to solving this math question:
Factor completely:
9x^2 + 9x -28
Found 2 solutions by Alan3354, ikleyn:
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
Factor completely:
9x^2 + 9x -28
--------------
Use trial and error.
It's (ax + c)*(bx + d)
-----
It'll be either
(x + c)*(9x + d) or
(3x + c)*(3x + d)
---------------
c*d = -28 so the signs are different.
---
The coefficient of x is odd, so either ad is odd and bc is even, or v.v.
=====================
It's gets easier with practice.
Answer by ikleyn(52786)   (Show Source): You can put this solution on YOUR website!
.

My rule is: 

    If I can not guess factoring in 5 seconds, I use the quadratic formula to find the roots 
    of the associated quadratic equation  and  


    As soon as I know the roots, the factoring form is  ,

    where coefficient "a" is the leading coefficient at x^2 in the original polynomial.



    Doing this way, I save my brain from unnecessary job.


RELATED QUESTIONS

Says to factor completely... (answered by solver91311)
What are the steps needed to solve this equation 4(9x - 1) = 9x(4 -... (answered by stanbon)
Factor the polynomial completely. 9x^2 -... (answered by robertb,Ex)
Factor completely, then place the answer in the proper location on the grid. 9x^2 + 9x (answered by Fombitz)
What are the steps to solving the following equation: -3(9x-7y)-(x+4y)? (answered by jim_thompson5910)
Factor completely. 9x^2 +... (answered by MRperkins)
hello. this is the problem that I have. (-9x^3+3x^2-15x)/(-3x) I do not think I did this (answered by Alan3354)
How would you factor x^2 + 9x + 18 ? What are the... (answered by Fombitz,Timnewman)
Combine and reduce to lowest terms. 9 / {{{9x^2+6x-8}}} - 6 / {{{9x^2-4}}}... (answered by Nate)