0=1.25x^2-30x+30

Solution for 0=1.25x^2-30x+30 equation:

0=1.25x^2-30x+30

We move all terms to the left:

0-(1.25x^2-30x+30)=0

We add all the numbers together, and all the variables

-(1.25x^2-30x+30)=0

We get rid of parentheses

-1.25x^2+30x-30=0

a = -1.25; b = 30; c = -30;
Δ = b2-4ac
Δ = 302-4·(-1.25)·(-30)
Δ = 750
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:

$\sqrt{\Delta}=\sqrt{750}=\sqrt{25*30}=\sqrt{25}*\sqrt{30}=5\sqrt{30}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-5\sqrt{30}}{2*-1.25}=\frac{-30-5\sqrt{30}}{-2.5}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+5\sqrt{30}}{2*-1.25}=\frac{-30+5\sqrt{30}}{-2.5}
$