x(5x-30)=0

Solution for x(5x-30)=0 equation:

x(5x-30)=0

We multiply parentheses

5x^2-30x=0

a = 5; b = -30; c = 0;
Δ = b2-4ac
Δ = -302-4·5·0
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-30}{2*5}=\frac{0}{10}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+30}{2*5}=\frac{60}{10}
=6
$