SOLUTION: My question is relating to 5x=-4x^2-2 I know I use the qadratic equation of x= -b+- b^2-4ac/2a. I can't put the square root sign in the fornula. anyways, near the end I have

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: My question is relating to 5x=-4x^2-2 I know I use the qadratic equation of x= -b+- b^2-4ac/2a. I can't put the square root sign in the fornula. anyways, near the end I have       Log On


   

Question 46159: My question is relating to 5x=-4x^2-2
I know I use the qadratic equation of x= -b+- b^2-4ac/2a. I can't put the square root sign in the fornula.
anyways, near the end I have a - on the top and bottom. do i only use the (i) on the top, or both?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Let's see.
Solve:
5x+=+-4x%5E2-2 Rewrite in standard form.
4x%5E2%2B5x%2B2+=+0 You are correct in using the quadratic formula because this does not factor. Here, a = 4, b = 5, and c = 2
x=%28-5%2B-sqrt%285%5E2-4%284%29%282%29%29%29%2F2%284%29
x=%28-5%2B-sqrt%2825-32%29%29%2F8
x=%28-5%2B-sqrt%28-7%29%29%2F8
The roots are:
x+=+-5%2F8%2B%28sqrt%287%29i%29%2F8
x+=+-5%2F8-%28sqrt%287%29i%29%2F8