2(x^2+16x-140)=0

Solution for 2(x^2+16x-140)=0 equation:

2(x^2+16x-140)=0

We multiply parentheses

2x^2+32x-280=0

a = 2; b = 32; c = -280;
Δ = b2-4ac
Δ = 322-4·2·(-280)
Δ = 3264
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:

$\sqrt{\Delta}=\sqrt{3264}=\sqrt{64*51}=\sqrt{64}*\sqrt{51}=8\sqrt{51}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(32)-8\sqrt{51}}{2*2}=\frac{-32-8\sqrt{51}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(32)+8\sqrt{51}}{2*2}=\frac{-32+8\sqrt{51}}{4}
$