-x^2+100x-979=0

Solution for -x^2+100x-979=0 equation:

-x^2+100x-979=0

We add all the numbers together, and all the variables

-1x^2+100x-979=0

a = -1; b = 100; c = -979;
Δ = b2-4ac
Δ = 1002-4·(-1)·(-979)
Δ = 6084
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6084}=78$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-78}{2*-1}=\frac{-178}{-2}
=+89
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+78}{2*-1}=\frac{-22}{-2}
=+11
$