-4b^2+19b+30=0

Solution for -4b^2+19b+30=0 equation:

-4b^2+19b+30=0

a = -4; b = 19; c = +30;
Δ = b2-4ac
Δ = 192-4·(-4)·30
Δ = 841
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{841}=29$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-29}{2*-4}=\frac{-48}{-8}
=+6
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+29}{2*-4}=\frac{10}{-8}
=-1+1/4
$