8x(x-6)=20

Solution for 8x(x-6)=20 equation:

8x(x-6)=20

We move all terms to the left:

8x(x-6)-(20)=0

We multiply parentheses

8x^2-48x-20=0

a = 8; b = -48; c = -20;
Δ = b2-4ac
Δ = -482-4·8·(-20)
Δ = 2944
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2944}=\sqrt{64*46}=\sqrt{64}*\sqrt{46}=8\sqrt{46}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-48)-8\sqrt{46}}{2*8}=\frac{48-8\sqrt{46}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-48)+8\sqrt{46}}{2*8}=\frac{48+8\sqrt{46}}{16}
$