SOLUTION: looking desperately for the answer to this: 6x to the second power - 12x - 18 = ???? Please help... thank you, krista m pooler

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: looking desperately for the answer to this: 6x to the second power - 12x - 18 = ???? Please help... thank you, krista m pooler      Log On


   

Question 39596: looking desperately for the answer to this:
6x to the second power - 12x - 18 = ????
Please help... thank you, krista m pooler
Found 3 solutions by askmemath, Nate, ikdeep:
Answer by askmemath(368) 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%2B-12x%2B-18+=+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=%28-12%29%5E2-4%2A6%2A-18=576.

Discriminant d=576 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--12%2B-sqrt%28+576+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-12%29%2Bsqrt%28+576+%29%29%2F2%5C6+=+3
x%5B2%5D+=+%28-%28-12%29-sqrt%28+576+%29%29%2F2%5C6+=+-1

Quadratic expression 6x%5E2%2B-12x%2B-18 can be factored:
6x%5E2%2B-12x%2B-18+=+6%28x-3%29%2A%28x--1%29
Again, the answer is: 3, -1. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+6%2Ax%5E2%2B-12%2Ax%2B-18+%29

Answer by Nate(3500) About Me  (Show Source):
You can put this solution on YOUR website!
6x to the second power - 12x - 18 = ????
6x^2 - 12x - 18 = ????
Any number you plug in for x will give you either -24 or higher.

Answer by ikdeep(226) About Me  (Show Source):
You can put this solution on YOUR website!
6x^2 - 12x - 18 = 0
divide both sides by 6 and we get...........
x^2 - 2x - 3 = 0
splitting of middle term and we get......
x^2 - (3-1)x - 3 = 0
x^2 - 3x + 1x - 3 = 0
x(x-3) +1(x-3) = 0
(x-3)(x+1)= 0
either x = 3 or = -1
hope this will help u