7b^2-13b-54=0

Solution for 7b^2-13b-54=0 equation:

7b^2-13b-54=0

a = 7; b = -13; c = -54;
Δ = b2-4ac
Δ = -132-4·7·(-54)
Δ = 1681
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1681}=41$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-13)-41}{2*7}=\frac{-28}{14}
=-2
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13)+41}{2*7}=\frac{54}{14}
=3+6/7
$