6x(90-x)=0

Solution for 6x(90-x)=0 equation:

6x(90-x)=0

We add all the numbers together, and all the variables

6x(-1x+90)=0

We multiply parentheses

-6x^2+540x=0

a = -6; b = 540; c = 0;
Δ = b2-4ac
Δ = 5402-4·(-6)·0
Δ = 291600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{291600}=540$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(540)-540}{2*-6}=\frac{-1080}{-12}
=+90
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(540)+540}{2*-6}=\frac{0}{-12}
=0
$