SOLUTION: Please help! Factor the polynomial 3x^2 -8x -5

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Question 327727: Please help! Factor the polynomial 3x^2 -8x -5
Answer by galactus(183) About Me  (Show Source):
You can put this solution on YOUR website!
As is, this one is not factorable in a nice way.
If it were 3x%5E2-8x%2B5, then it would be (x-1)(3x-5)
But, as is, it has solutions -%28sqrt%2831%29-4%29%2F3 and %28sqrt%2831%29%2B4%29%2F3.
Here is a trick to tell rather or not a quadratic is factorable or not before you spend time wrestling with it and it turns out it is not factorable.
Check the discriminant. It is b%5E2-4ac
You may recognize this as what is inside the parentheses in the quadratic formula.
Anyway, a=3, b=-8, c=-5
%28-8%29%5E2-4%283%29%28-5%29=124
If, when you check the discrimiant, the result is not a perfect square, then it is NOT factorable. 124 is not a perfect square, so it is not factorable.
The other case I mentioned, 3x%5E2-8x%2B5
It has discriminant equal to 4. That is a perfect square. So it is factorable, as was shown.
Like that?.