SOLUTION: (x + 10) * (3x + 2) Distributive property over addition, I need help finding "X" and how to do this problem period

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Question 274319: (x + 10) * (3x + 2)
Distributive property over addition, I need help finding "X" and how to do this problem period
Answer by JBarnum(2146) About Me  (Show Source):
You can put this solution on YOUR website!
use foil method
%28x%2B10%29%283x%2B2%29
FOIL
first x%2A3x=3x%5E2
outerx%2A2=2x
inner10%2A3x=30x
last10%2A2=20
3x%5E2%2B2x%2B30x%2B20
3x%5E2%2B32x%2B20use quadratic formula to solve
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 3x%5E2%2B32x%2B20+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%2832%29%5E2-4%2A3%2A20=784.

Discriminant d=784 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-32%2B-sqrt%28+784+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2832%29%2Bsqrt%28+784+%29%29%2F2%5C3+=+-0.666666666666667
x%5B2%5D+=+%28-%2832%29-sqrt%28+784+%29%29%2F2%5C3+=+-10

Quadratic expression 3x%5E2%2B32x%2B20 can be factored:
3x%5E2%2B32x%2B20+=+3%28x--0.666666666666667%29%2A%28x--10%29
Again, the answer is: -0.666666666666667, -10. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+3%2Ax%5E2%2B32%2Ax%2B20+%29