SOLUTION: 1. Solve. Try factoring first. If factoring is not possible or is difficult, use the quadratic formula. 2x2 + 8x = - 1 2.Solve for the specified variable. S = a/

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: 1. Solve. Try factoring first. If factoring is not possible or is difficult, use the quadratic formula. 2x2 + 8x = - 1 2.Solve for the specified variable. S = a/      Log On


   

Question 280119: 1. Solve. Try factoring first. If factoring is not possible or is difficult, use the quadratic formula.
2x2 + 8x = - 1
2.Solve for the specified variable. S = a/1 - r
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Solve. Try factoring first. If factoring is not possible or is difficult, use the quadratic formula.
2x2 + 8x = - 1
2x%5E2+%2B+8x+%2B+1+=+0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 2x%5E2%2B8x%2B1+=+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=%288%29%5E2-4%2A2%2A1=56.

Discriminant d=56 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-8%2B-sqrt%28+56+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%288%29%2Bsqrt%28+56+%29%29%2F2%5C2+=+-0.129171306613029
x%5B2%5D+=+%28-%288%29-sqrt%28+56+%29%29%2F2%5C2+=+-3.87082869338697

Quadratic expression 2x%5E2%2B8x%2B1 can be factored:
2x%5E2%2B8x%2B1+=+%28x--0.129171306613029%29%2A%28x--3.87082869338697%29
Again, the answer is: -0.129171306613029, -3.87082869338697. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B8%2Ax%2B1+%29

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2.Solve for the specified variable. S = a/1 - r
Which variable?