10x(5x-3)=20

Solution for 10x(5x-3)=20 equation:

10x(5x-3)=20

We move all terms to the left:

10x(5x-3)-(20)=0

We multiply parentheses

50x^2-30x-20=0

a = 50; b = -30; c = -20;
Δ = b2-4ac
Δ = -302-4·50·(-20)
Δ = 4900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4900}=70$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-70}{2*50}=\frac{-40}{100}
=-2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+70}{2*50}=\frac{100}{100}
=1
$