7b^2+8b-12=0

Solution for 7b^2+8b-12=0 equation:

7b^2+8b-12=0

a = 7; b = 8; c = -12;
Δ = b2-4ac
Δ = 82-4·7·(-12)
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-20}{2*7}=\frac{-28}{14}
=-2
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+20}{2*7}=\frac{12}{14}
=6/7
$