25b^2+25b-30=0

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

25b^2+25b-30=0

a = 25; b = 25; c = -30;
Δ = b2-4ac
Δ = 252-4·25·(-30)
Δ = 3625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3625}=\sqrt{25*145}=\sqrt{25}*\sqrt{145}=5\sqrt{145}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-5\sqrt{145}}{2*25}=\frac{-25-5\sqrt{145}}{50}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+5\sqrt{145}}{2*25}=\frac{-25+5\sqrt{145}}{50}
$