0=3x^2-30x+72

Solution for 0=3x^2-30x+72 equation:

0=3x^2-30x+72

We move all terms to the left:

0-(3x^2-30x+72)=0

We add all the numbers together, and all the variables

-(3x^2-30x+72)=0

We get rid of parentheses

-3x^2+30x-72=0

a = -3; b = 30; c = -72;
Δ = b2-4ac
Δ = 302-4·(-3)·(-72)
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-6}{2*-3}=\frac{-36}{-6}
=+6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+6}{2*-3}=\frac{-24}{-6}
=+4
$