-2x^2-16x+3=0

Solution for -2x^2-16x+3=0 equation:

-2x^2-16x+3=0

a = -2; b = -16; c = +3;
Δ = b2-4ac
Δ = -162-4·(-2)·3
Δ = 280
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:

$\sqrt{\Delta}=\sqrt{280}=\sqrt{4*70}=\sqrt{4}*\sqrt{70}=2\sqrt{70}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-2\sqrt{70}}{2*-2}=\frac{16-2\sqrt{70}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+2\sqrt{70}}{2*-2}=\frac{16+2\sqrt{70}}{-4}
$