Question 307969: i need to solve for x
3x^2+3x-126=0
Answer by rapaljer(4671)   (Show Source):
You can put this solution on YOUR website! 3x^2+3x-126=0
This is a quadratic equation that must be solved by factoring! The first step in factoring is to take out the common factor, in this case, 3.
3(x^2+x-42)=0
Next, factor the trinomial:
3(x+7)(x-6)=0
The 3 does not give any solutions to this problem.
First solution:
(x+7)=0
x=-7
Second solution:
(x-6)=0
x=6
For additional help with solving quadratic equations by factoring, please see my own website. To find my website, click on my tutor name "Rapaljer" anywhere in algebra.com. Then, look for the link on my Homepage "Basic, Intermediate, and College Algebra: One Step at a Time." Choose "Basic Algebra", "Chapter 2", and look for "Section 2.09 Solving Quadratic Equations by Factoring." If you have trouble with the FACTORING, then these skills are also taught in Chapter 2. See also the "MATH IN LIVING COLOR" pages that go with this explanation, where the exercises are solved IN COLOR!
Dr. Robert J. Rapalje, Retired
Seminole State College of Florida
Altamonte Springs Campus
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