15x+285=x^2+2x

Solution for 15x+285=x^2+2x equation:

15x+285=x^2+2x

We move all terms to the left:

15x+285-(x^2+2x)=0

We get rid of parentheses

-x^2+15x-2x+285=0

We add all the numbers together, and all the variables

-1x^2+13x+285=0

a = -1; b = 13; c = +285;
Δ = b2-4ac
Δ = 132-4·(-1)·285
Δ = 1309
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-\sqrt{1309}}{2*-1}=\frac{-13-\sqrt{1309}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+\sqrt{1309}}{2*-1}=\frac{-13+\sqrt{1309}}{-2}
$