SOLUTION: Please help me factor the polynomial 15y^2-y-28

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Question 61945: Please help me factor the polynomial 15y^2-y-28
Found 2 solutions by stanbon, ankor@dixie-net.com:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
factor the polynomial
15y^2-y-28
15y^2-21y+20y-28
=3y(5y-7)+4(5y-7)
=(5y-7)(3y+4)
Cheers,
Stan H.

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
factor the polynomial 15y^2 - y - 28
:
This is a "try and see situation"
Assume that the factors of 28; 4 & 7 are involved, 14 & 2 are also factors but since the middle coefficient is -1, it's not likely
:
Start with this: (__x - 4)(__x + 7)
:
Try various factors of 15, put the signs in to satisfy the coefficient of the middle term, -1
Try 3 & 5
(3x + 4)(5x - 7) = 0
:
fOIL it to be sure you have it:
15x^2 - 21x + 20x - 28 confirms it
:
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