SOLUTION: Solve by completing the square:4x^2+8x-7=0.Express roots in EXACT radical form.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve by completing the square:4x^2+8x-7=0.Express roots in EXACT radical form.      Log On


   

Question 121032: Solve by completing the square:4x^2+8x-7=0.Express roots in EXACT radical form.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
4x%5E2%2B8x-7=0
x%5E2%2B2x-7%2F4=0Divide both sides by 4.
x%5E2%2B2x-7%2F4%2B1=1Add 1 to both sides of the equation
%28x%5E2%2B2x%2B1%29-7%2F4=1
%28x%2B1%29%5E2-7%2F4=1 Complete the square.
%28x%2B1%29%5E2=1%2B7%2F4Add 7/4 both sides.
%28x%2B1%29%5E2=4%2F4%2B7%2F4Same denominator on the right hand side.
%28x%2B1%29%5E2=11%2F4
1.+x%2B1=sqrt%2811%29%2F2First solution
x=sqrt%2811%29%2F2-1
2. x%2B1=-sqrt%2811%29%2F2Second solution
x=-sqrt%2811%29%2F2-1