Xx(0,4XY)=378

Solution for Xx(0,4XY)=378 equation:

XX(0.4X)=378

We move all terms to the left:

XX(0.4X)-(378)=0

We add all the numbers together, and all the variables

XX(+0.4X)-378=0

We multiply parentheses

0X^2-378=0

We add all the numbers together, and all the variables

X^2-378=0

a = 1; b = 0; c = -378;
Δ = b2-4ac
Δ = 02-4·1·(-378)
Δ = 1512
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:

$\sqrt{\Delta}=\sqrt{1512}=\sqrt{36*42}=\sqrt{36}*\sqrt{42}=6\sqrt{42}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-6\sqrt{42}}{2*1}=\frac{0-6\sqrt{42}}{2}
=-\frac{6\sqrt{42}}{2}
=-3\sqrt{42}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+6\sqrt{42}}{2*1}=\frac{0+6\sqrt{42}}{2}
=\frac{6\sqrt{42}}{2}
=3\sqrt{42}
$