-x^2+15x+700=0

Solution for -x^2+15x+700=0 equation:

-x^2+15x+700=0

We add all the numbers together, and all the variables

-1x^2+15x+700=0

a = -1; b = 15; c = +700;
Δ = b2-4ac
Δ = 152-4·(-1)·700
Δ = 3025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3025}=55$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-55}{2*-1}=\frac{-70}{-2}
=+35
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+55}{2*-1}=\frac{40}{-2}
=-20
$