(3x*5)(2x-4)-20=0

Solution for (3x*5)(2x-4)-20=0 equation:

(3x*5)(2x-4)-20=0

We add all the numbers together, and all the variables

(+3x*5)(2x-4)-20=0

We multiply parentheses ..

(+30x^2-60x)-20=0

We get rid of parentheses

30x^2-60x-20=0

a = 30; b = -60; c = -20;
Δ = b2-4ac
Δ = -602-4·30·(-20)
Δ = 6000
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:

$\sqrt{\Delta}=\sqrt{6000}=\sqrt{400*15}=\sqrt{400}*\sqrt{15}=20\sqrt{15}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-20\sqrt{15}}{2*30}=\frac{60-20\sqrt{15}}{60}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+20\sqrt{15}}{2*30}=\frac{60+20\sqrt{15}}{60}
$