SOLUTION: I am requesting assistance with the following quadratic equation (x-2)(x^2-8x+7) thank you

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: I am requesting assistance with the following quadratic equation (x-2)(x^2-8x+7) thank you      Log On


   



Question 246113: I am requesting assistance with the following quadratic equation
(x-2)(x^2-8x+7)
thank you

Found 2 solutions by rapaljer, marcsam823:
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
This is not an equation! An equation has to have an "equals" sign in it. Did you mean this:
(x-2)(x^2-8x+7)=0


Start by factoring it:
(x-2)(x-7)(x-1)=0

Now, since there are THREE factors, there will be THREE answers:

First,
x-2=0
x=2

Second,
x-7=0
x=7

Third,
x-1=0
x=1

For additional explanation on this topic, try my own website. Click on my tutor name "Rapaljer" anywhere in algebra.com. This takes you to my Homepage. From my Homepage, look for the link "Basic, Intermediate, and College Algebra: One Step at a Time." Choose "Basic Algebra", then look in "Chapter 2" for "Section 2.09 Solving Quadratic Equations by Factoring."

My explanations are written for students who usually have trouble understanding math, and my own students say they can understand it a LOT easier than traditional textbooks. It is also supported by my "MATH IN LIVING COLOR" pages in which I solved the hardest problems IN COLOR! If you like my website, please recommend it to family and friends. It's all FREE!!

One more thought, if you had trouble with the factoring of this problem or any other problems with factoring, please see my FACTORING sections, which are near the beginning of this very same chapter. If you need help with factoring, I even have a free video of me teaching this lesson in my own classroom a few years ago. The video is also available FREE on my website!!

Dr. Robert J. Rapalje, Retired
Seminole State College of Florida
Altamonte Springs Campus

Answer by marcsam823(57) About Me  (Show Source):
You can put this solution on YOUR website!
%28x-2%29%28x%5E2-8x%2B7%29

Multiply each term in the secnd set of parentheses by the first term in the first parentheses (x):
x%28x%5E2+-+8x+%2B7%29
x%28x%5E2%29-+x%288x%29+%2B+x%287%29
x%5E3+-+8x%5E2+%2B+7x

Next, multiply each term in the secnd set of parentheses by the second term in the first parentheses (-2):

-2%28x%5E2+-+8x+%2B7%29
-2%28x%5E2%29-+%28-2%29%288x%29+%2B+-2%287%29
-2x%5E2+%2B16x+-+14


Add the first expression to the second:
x%5E3+-+8x%5E2+%2B+7x + -2x%5E2+%2B16x+-+14


Simplify by combinig like terms:

x%5E3+-+10x%5E2+%2B+23x+-+14
This is your answer.