x*2x=1390

Solution for x*2x=1390 equation:

x*2x=1390

We move all terms to the left:

x*2x-(1390)=0

Wy multiply elements

2x^2-1390=0

a = 2; b = 0; c = -1390;
Δ = b2-4ac
Δ = 02-4·2·(-1390)
Δ = 11120
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:

$\sqrt{\Delta}=\sqrt{11120}=\sqrt{16*695}=\sqrt{16}*\sqrt{695}=4\sqrt{695}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{695}}{2*2}=\frac{0-4\sqrt{695}}{4}
=-\frac{4\sqrt{695}}{4}
=-\sqrt{695}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{695}}{2*2}=\frac{0+4\sqrt{695}}{4}
=\frac{4\sqrt{695}}{4}
=\sqrt{695}
$