2x^2-41x-21=0

Solution for 2x^2-41x-21=0 equation:

2x^2-41x-21=0

a = 2; b = -41; c = -21;
Δ = b2-4ac
Δ = -412-4·2·(-21)
Δ = 1849
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1849}=43$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-41)-43}{2*2}=\frac{-2}{4}
=-1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-41)+43}{2*2}=\frac{84}{4}
=21
$