4x2-20x=11

Solution for 4x2-20x=11 equation:

4x^2-20x=11

We move all terms to the left:

4x^2-20x-(11)=0

a = 4; b = -20; c = -11;
Δ = b2-4ac
Δ = -202-4·4·(-11)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-24}{2*4}=\frac{-4}{8}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+24}{2*4}=\frac{44}{8}
=5+1/2
$