SOLUTION: x2 + 12x − 1 = 0 x2 + 12x − 1 + 1 = 0 + 1 x2 + 12x = 1

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Question 939144: x2 + 12x − 1 = 0
x2 + 12x − 1 + 1 = 0 + 1
x2 + 12x = 1
Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
Given: X%5E2+%2B+12X+-+1+=+0
Since the equation is already set to zero, all you have to do is use the quadratic equation.
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation aX%5E2%2BbX%2Bc=0 (in our case 1X%5E2%2B12X%2B-1+=+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=%2812%29%5E2-4%2A1%2A-1=148.

Discriminant d=148 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-12%2B-sqrt%28+148+%29%29%2F2%5Ca.

X%5B1%5D+=+%28-%2812%29%2Bsqrt%28+148+%29%29%2F2%5C1+=+0.0827625302982193
X%5B2%5D+=+%28-%2812%29-sqrt%28+148+%29%29%2F2%5C1+=+-12.0827625302982

Quadratic expression 1X%5E2%2B12X%2B-1 can be factored:
1X%5E2%2B12X%2B-1+=+1%28X-0.0827625302982193%29%2A%28X--12.0827625302982%29
Again, the answer is: 0.0827625302982193, -12.0827625302982. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B12%2Ax%2B-1+%29

When rounded X equals 0.083 and -12.083