r2-246r-30240=0

Solution for r2-246r-30240=0 equation:

r2-246r-30240=0

We add all the numbers together, and all the variables

r^2-246r-30240=0

a = 1; b = -246; c = -30240;
Δ = b2-4ac
Δ = -2462-4·1·(-30240)
Δ = 181476
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{181476}=426$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-246)-426}{2*1}=\frac{-180}{2}
=-90
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-246)+426}{2*1}=\frac{672}{2}
=336
$