SOLUTION: help? Factor completely. If a polynomial is prime, state this −70a^4 + 68a^3 − 16a^2

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Question 601656: help?
Factor completely. If a polynomial is prime, state this
−70a^4 + 68a^3 − 16a^2
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
-70a4 + 68a³ - 16a²

First we look for a number we can factor out.  The largest whole number
that will divide evenly into 70, 68, and 16 is 2 and since the term with
the largest exponent is negative we us -2.

No we look for the largest power of a letter that we can factor out from all
the terms.  That's a²

So we factor out -2a² and get

-2a²(35a² - 34a + 8) 

Then we factor what's in the parentheses either by "the backwards FOIL 
trial and error" method or by the AC-method found here:  

http://www.algebra.com/my/change_this_name32371.lesson?content_action=show_dev

-2a²(7a-4)(5a-2)

Edwin