2X^2-8x-55=0

Solution for 2X^2-8x-55=0 equation:

2X^2-8X-55=0

a = 2; b = -8; c = -55;
Δ = b2-4ac
Δ = -82-4·2·(-55)
Δ = 504
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{504}=\sqrt{36*14}=\sqrt{36}*\sqrt{14}=6\sqrt{14}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-6\sqrt{14}}{2*2}=\frac{8-6\sqrt{14}}{4}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+6\sqrt{14}}{2*2}=\frac{8+6\sqrt{14}}{4}
$