I'm stuck on this question

It's solving the quadratic equation by completing the square

4x^2-x=8

Any help?

Printable View

- Oct 14th 2009, 09:36 PMMistQuadratic Equation
I'm stuck on this question

It's solving the quadratic equation by completing the square

4x^2-x=8

Any help? - Oct 14th 2009, 09:59 PMearboth
$\displaystyle x^2-\dfrac14x=2$ .........

**Divide by the leading factor**

$\displaystyle x^2-\dfrac14x+\dfrac1{64}=2 + \dfrac1{64}$ .........**take the half of the factor of x and square it. Add the square on both sides of the equation.**

$\displaystyle \left(x-\dfrac18\right)^2= \dfrac{129}{64}$ .........**Transform the LHS into a complete square.**

Calculate the square-root on both sides and solve for x.