SOLUTION: Would you pls help me with this? Solve using quadratic formula: 6x^2 + 7x - 11 = 0 I started like this: x= {-7+-sqrt(7^2-4*66)}/ 12 I would like to know how to do it step b

Algebra ->  Graphs -> SOLUTION: Would you pls help me with this? Solve using quadratic formula: 6x^2 + 7x - 11 = 0 I started like this: x= {-7+-sqrt(7^2-4*66)}/ 12 I would like to know how to do it step b      Log On


   

Question 621635: Would you pls help me with this?
Solve using quadratic formula: 6x^2 + 7x - 11 = 0
I started like this:

x= {-7+-sqrt(7^2-4*66)}/ 12
I would like to know how to do it step by step because I want to be able to do the others by myself.

Thanks a lot.
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 6x%5E2%2B7x%2B-11+=+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=%287%29%5E2-4%2A6%2A-11=313.

Discriminant d=313 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-7%2B-sqrt%28+313+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%287%29%2Bsqrt%28+313+%29%29%2F2%5C6+=+0.890983834412844
x%5B2%5D+=+%28-%287%29-sqrt%28+313+%29%29%2F2%5C6+=+-2.05765050107951

Quadratic expression 6x%5E2%2B7x%2B-11 can be factored:
6x%5E2%2B7x%2B-11+=+6%28x-0.890983834412844%29%2A%28x--2.05765050107951%29
Again, the answer is: 0.890983834412844, -2.05765050107951. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+6%2Ax%5E2%2B7%2Ax%2B-11+%29