SOLUTION: I am trying to figure out how to solve polynomial equations and my instructor is not very good at explaining things so that I understand them. Can someone explain to me how to solv

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Question 409459: I am trying to figure out how to solve polynomial equations and my instructor is not very good at explaining things so that I understand them. Can someone explain to me how to solve polynomial equations. Example:
(4x+9)(15x^2-7x-2)=0
I don't understand algebra at all, and I'm lacking the help from my instructor.
Found 2 solutions by ewatrrr, Alan3354:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

Solving

(4x+9)(15x^2-7x-2) =0    |the concept is finding products = 0 to solve for x

factoring further:

factoring the (15x^2-7x-2)portion: factoring: expressing as 2 products..

In this case: (_x    1)(_x   2)|the hint here is the -7x middle term

         (4x+9)(5x + 1)(3x - 2)= 0 |strategically placing the 5 and 3 & ± works

      Note:SUM of the inner product(3x) and the outer product(-10x) = -7x

(4x+9)(5x+1)(3x -2)= 0  |NOW we are prepared to solve for x(s)

(4x+9)= 0    x = -9/4

(5x+1)= 0    x = -1/5

(3x -2)= 0   x = 2/3

Solution set is x = {-9/4,-1/5,2/3}

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
(4x+9)(15x^2-7x-2)=0
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If the product is zero, then one of the factors must be zero. See that?
If (4x+9) = 0
4x = -9
x = -9/4
--------
If (15x^2-7x-2)=0
This is not as obvious, but you can factor it:
(5x+1)*(3x-2) = 0
Then either (5x+1) = 0 --> x = -1/5
----------
or (3x-2) = 0 --> x = 2/3
--------------
The 3 solutions are
x = -9/4
x = -1/5
x = 2/3