0=x^2+15x-16

Solution for 0=x^2+15x-16 equation:

0=x^2+15x-16

We move all terms to the left:

0-(x^2+15x-16)=0

We add all the numbers together, and all the variables

-(x^2+15x-16)=0

We get rid of parentheses

-x^2-15x+16=0

We add all the numbers together, and all the variables

-1x^2-15x+16=0

a = -1; b = -15; c = +16;
Δ = b2-4ac
Δ = -152-4·(-1)·16
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-17}{2*-1}=\frac{-2}{-2}
=1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+17}{2*-1}=\frac{32}{-2}
=-16
$