2b^2-4b-126=0

Solution for 2b^2-4b-126=0 equation:

2b^2-4b-126=0

a = 2; b = -4; c = -126;
Δ = b2-4ac
Δ = -42-4·2·(-126)
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-32}{2*2}=\frac{-28}{4}
=-7
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+32}{2*2}=\frac{36}{4}
=9
$