0=25x^2+50x-70

Solution for 0=25x^2+50x-70 equation:

0=25x^2+50x-70

We move all terms to the left:

0-(25x^2+50x-70)=0

We add all the numbers together, and all the variables

-(25x^2+50x-70)=0

We get rid of parentheses

-25x^2-50x+70=0

a = -25; b = -50; c = +70;
Δ = b2-4ac
Δ = -502-4·(-25)·70
Δ = 9500
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:

$\sqrt{\Delta}=\sqrt{9500}=\sqrt{100*95}=\sqrt{100}*\sqrt{95}=10\sqrt{95}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-50)-10\sqrt{95}}{2*-25}=\frac{50-10\sqrt{95}}{-50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-50)+10\sqrt{95}}{2*-25}=\frac{50+10\sqrt{95}}{-50}
$