SOLUTION: solve by using the Quadratic formula xsqrt+4x-1=0 i try for hours not right

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Question 116528: solve by using the Quadratic formula xsqrt+4x-1=0 i try for hours not right
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!
I'm guessing a little, but I think you meant x%5E2%2B4x-1=0.

Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B4x%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=%284%29%5E2-4%2A1%2A-1=20.

Discriminant d=20 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-4%2B-sqrt%28+20+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%284%29%2Bsqrt%28+20+%29%29%2F2%5C1+=+0.23606797749979
x%5B2%5D+=+%28-%284%29-sqrt%28+20+%29%29%2F2%5C1+=+-4.23606797749979

Quadratic expression 1x%5E2%2B4x%2B-1 can be factored:
1x%5E2%2B4x%2B-1+=+1%28x-0.23606797749979%29%2A%28x--4.23606797749979%29
Again, the answer is: 0.23606797749979, -4.23606797749979. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B4%2Ax%2B-1+%29



Instead of calculating the answer to a bunch of meaningless decimal places like this solver does, I would just leave the answer in terms of a radical.

x=%28-4%2B-sqrt%2820%29%29%2F2
x=%28-4%2B2%2Asqrt%285%29%29%2F2 or x=%28-4-2%2Asqrt%285%29%29%2F2
x=-2%2Bsqrt%285%29 or x=-2-sqrt%285%29