SOLUTION: x^2 + 12x = 64

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: x^2 + 12x = 64      Log On


   

Question 939799: x^2 + 12x = 64
Answer by srinivas.g(540) About Me  (Show Source):
You can put this solution on YOUR website!
x%5E2%2B12x=64
Move 64 to the left
x%5E2%2B12X-64=0
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B12x%2B-64+=+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-64=400.

Discriminant d=400 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-12%2B-sqrt%28+400+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2812%29%2Bsqrt%28+400+%29%29%2F2%5C1+=+4
x%5B2%5D+=+%28-%2812%29-sqrt%28+400+%29%29%2F2%5C1+=+-16

Quadratic expression 1x%5E2%2B12x%2B-64 can be factored:
1x%5E2%2B12x%2B-64+=+1%28x-4%29%2A%28x--16%29
Again, the answer is: 4, -16. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B12%2Ax%2B-64+%29
]