2x^2=1400

Solution for 2x^2=1400 equation:

2x^2=1400

We move all terms to the left:

2x^2-(1400)=0

a = 2; b = 0; c = -1400;
Δ = b2-4ac
Δ = 02-4·2·(-1400)
Δ = 11200
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:

$\sqrt{\Delta}=\sqrt{11200}=\sqrt{1600*7}=\sqrt{1600}*\sqrt{7}=40\sqrt{7}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-40\sqrt{7}}{2*2}=\frac{0-40\sqrt{7}}{4}
=-\frac{40\sqrt{7}}{4}
=-10\sqrt{7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+40\sqrt{7}}{2*2}=\frac{0+40\sqrt{7}}{4}
=\frac{40\sqrt{7}}{4}
=10\sqrt{7}
$