2400=40x2

Solution for 2400=40x2 equation:

2400=40x^2

We move all terms to the left:

2400-(40x^2)=0

a = -40; b = 0; c = +2400;
Δ = b2-4ac
Δ = 02-4·(-40)·2400
Δ = 384000
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:

$\sqrt{\Delta}=\sqrt{384000}=\sqrt{25600*15}=\sqrt{25600}*\sqrt{15}=160\sqrt{15}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-160\sqrt{15}}{2*-40}=\frac{0-160\sqrt{15}}{-80}
=-\frac{160\sqrt{15}}{-80}
=-\frac{2\sqrt{15}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+160\sqrt{15}}{2*-40}=\frac{0+160\sqrt{15}}{-80}
=\frac{160\sqrt{15}}{-80}
=\frac{2\sqrt{15}}{-1}
$