20x^2-11x=4=0

Solution for 20x^2-11x=4=0 equation:

20x^2-11x=4=0

We move all terms to the left:

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

a = 20; b = -11; c = -4;
Δ = b2-4ac
Δ = -112-4·20·(-4)
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-11)-21}{2*20}=\frac{-10}{40}
=-1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+21}{2*20}=\frac{32}{40}
=4/5
$