101=5x*4x

Solution for 101=5x*4x equation:

101=5x*4x

We move all terms to the left:

101-(5x*4x)=0

We add all the numbers together, and all the variables

-(+5x*4x)+101=0

We get rid of parentheses

-5x*4x+101=0

Wy multiply elements

-20x^2+101=0

a = -20; b = 0; c = +101;
Δ = b2-4ac
Δ = 02-4·(-20)·101
Δ = 8080
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:

$\sqrt{\Delta}=\sqrt{8080}=\sqrt{16*505}=\sqrt{16}*\sqrt{505}=4\sqrt{505}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{505}}{2*-20}=\frac{0-4\sqrt{505}}{-40}
=-\frac{4\sqrt{505}}{-40}
=-\frac{\sqrt{505}}{-10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{505}}{2*-20}=\frac{0+4\sqrt{505}}{-40}
=\frac{4\sqrt{505}}{-40}
=\frac{\sqrt{505}}{-10}
$