0=25x^2+15x-3

Solution for 0=25x^2+15x-3 equation:

0=25x^2+15x-3

We move all terms to the left:

0-(25x^2+15x-3)=0

We add all the numbers together, and all the variables

-(25x^2+15x-3)=0

We get rid of parentheses

-25x^2-15x+3=0

a = -25; b = -15; c = +3;
Δ = b2-4ac
Δ = -152-4·(-25)·3
Δ = 525
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:

$\sqrt{\Delta}=\sqrt{525}=\sqrt{25*21}=\sqrt{25}*\sqrt{21}=5\sqrt{21}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-5\sqrt{21}}{2*-25}=\frac{15-5\sqrt{21}}{-50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+5\sqrt{21}}{2*-25}=\frac{15+5\sqrt{21}}{-50}
$