3(x-5)(-x+6)=0

Solution for 3(x-5)(-x+6)=0 equation:

3(x-5)(-x+6)=0

We add all the numbers together, and all the variables

3(x-5)(-1x+6)=0

We multiply parentheses ..

3(-1x^2+6x+5x-30)=0

We multiply parentheses

-3x^2+18x+15x-90=0

We add all the numbers together, and all the variables

-3x^2+33x-90=0

a = -3; b = 33; c = -90;
Δ = b2-4ac
Δ = 332-4·(-3)·(-90)
Δ = 9
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{9}=3$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(33)-3}{2*-3}=\frac{-36}{-6}
=+6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(33)+3}{2*-3}=\frac{-30}{-6}
=+5
$