SOLUTION: Hello, i'm trying to solve this: x^2-2x-4=0. I mean x to the 2nd power minus 2x minus 4 =0 okay, i tried to FOIL this problem and it doesn't work. please help.

Algebra ->  Equations -> SOLUTION: Hello, i'm trying to solve this: x^2-2x-4=0. I mean x to the 2nd power minus 2x minus 4 =0 okay, i tried to FOIL this problem and it doesn't work. please help.      Log On


   

Question 122573: Hello, i'm trying to solve this: x^2-2x-4=0. I mean x to the 2nd power minus 2x minus 4 =0 okay, i tried to FOIL this problem and it doesn't work. please help.
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
FOIL DOESN'T WORK FOR THESE EQUATIONS.
YOU NEED THE QUADRATIC EQUATION TO SOLVE THIS ONE.
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
X^2-2X-4=0
X=(2+-SQRT[-2^2-4*1*-4])/2*1
X=(2+-SQRT[4+16])/2
X=(2+-SQRT20)/2
X=(2+4.472)/2
X=(2+4.472)/2
X=6.472/2
X=3.236 ANSWER.
X=(2-4.472)/2
X=-2.472/2
X=-1.236 ANSWER.