2z^2+24z-90=0

Solution for 2z^2+24z-90=0 equation:

2z^2+24z-90=0

a = 2; b = 24; c = -90;
Δ = b2-4ac
Δ = 242-4·2·(-90)
Δ = 1296
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1296}=36$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(24)-36}{2*2}=\frac{-60}{4}
=-15
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(24)+36}{2*2}=\frac{12}{4}
=3
$