SOLUTION: How do you foil in reverse? When two numbers multipled together equal the last number of the equation and then the same two numbers must add up to te number in the middle of the e

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Question 515015: How do you foil in reverse? When two numbers multipled together equal the last number of the equation and then the same two numbers must add up to te number in the middle of the equation. Is there a trick to solving these? Example:29y+41+50
Found 2 solutions by josmiceli, Alan3354:
Answer by josmiceli(9680) About Me  (Show Source):
You can put this solution on YOUR website!
I think there is a method where complex numbers are used.
There is a book by The physicist George Gamow called
1-2-3 infinity in which he uses complex numbers to
find a buried treasure. I'm not sure if that can be directly
applied or not.

Answer by Alan3354(30993) About Me  (Show Source):
You can put this solution on YOUR website!
How do you foil in reverse? When two numbers multipled together equal the last number of the equation and then the same two numbers must add up to te number in the middle of the equation. Is there a trick to solving these? Example:29y+41+50
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If it's 2nd order, use the quadratic equation
eg, x^2 + 4x - 7
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Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B4x%2B-7+=+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=%284%29%5E2-4%2A1%2A-7=44.

Discriminant d=44 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-4%2B-sqrt%28+44+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%284%29%2Bsqrt%28+44+%29%29%2F2%5C1+=+1.3166247903554
x%5B2%5D+=+%28-%284%29-sqrt%28+44+%29%29%2F2%5C1+=+-5.3166247903554

Quadratic expression 1x%5E2%2B4x%2B-7 can be factored:
1x%5E2%2B4x%2B-7+=+%28x-1.3166247903554%29%2A%28x--5.3166247903554%29
Again, the answer is: 1.3166247903554, -5.3166247903554. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B4%2Ax%2B-7+%29

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x^2 + 4x - 7 = (x - 1.3166)*(x + 5.3166)
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Your example: 29y+41+50 = 29y + 91 isn't a good one.