7b^2+30b+8=0

Solution for 7b^2+30b+8=0 equation:

7b^2+30b+8=0

a = 7; b = 30; c = +8;
Δ = b2-4ac
Δ = 302-4·7·8
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-26}{2*7}=\frac{-56}{14}
=-4
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+26}{2*7}=\frac{-4}{14}
=-2/7
$