5z^2+25z-30=0

Solution for 5z^2+25z-30=0 equation:

5z^2+25z-30=0

a = 5; b = 25; c = -30;
Δ = b2-4ac
Δ = 252-4·5·(-30)
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-35}{2*5}=\frac{-60}{10}
=-6
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+35}{2*5}=\frac{10}{10}
=1
$