You can put this solution on YOUR website! 3r^2+10r-8
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It will be (r + ?)*(3r + ?), call it (r + a)*(3r + b)
a & b will be either 1 & 8 or 2 & 4, the only factors of 8.
The signs of a & b will be different since the product is -8.
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(r - 1)*(3r + 8) --> +5r, not it
(r - 2)*(3r + 4) --> -2r, not it
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(r - 4)*(3r + 2) --> -10r, the 10 is right, swap the signs
