8x^2+16x-448=0

Solution for 8x^2+16x-448=0 equation:

8x^2+16x-448=0

a = 8; b = 16; c = -448;
Δ = b2-4ac
Δ = 162-4·8·(-448)
Δ = 14592
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:

$\sqrt{\Delta}=\sqrt{14592}=\sqrt{256*57}=\sqrt{256}*\sqrt{57}=16\sqrt{57}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-16\sqrt{57}}{2*8}=\frac{-16-16\sqrt{57}}{16}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+16\sqrt{57}}{2*8}=\frac{-16+16\sqrt{57}}{16}
$