42b^2-13b-42=0

Solution for 42b^2-13b-42=0 equation:

42b^2-13b-42=0

a = 42; b = -13; c = -42;
Δ = b2-4ac
Δ = -132-4·42·(-42)
Δ = 7225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7225}=85$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-13)-85}{2*42}=\frac{-72}{84}
=-6/7
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-13)+85}{2*42}=\frac{98}{84}
=1+1/6
$