0=5x^2-70x+225

Solution for 0=5x^2-70x+225 equation:

0=5x^2-70x+225

We move all terms to the left:

0-(5x^2-70x+225)=0

We add all the numbers together, and all the variables

-(5x^2-70x+225)=0

We get rid of parentheses

-5x^2+70x-225=0

a = -5; b = 70; c = -225;
Δ = b2-4ac
Δ = 702-4·(-5)·(-225)
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(70)-20}{2*-5}=\frac{-90}{-10}
=+9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(70)+20}{2*-5}=\frac{-50}{-10}
=+5
$