20=16x*9x

Solution for 20=16x*9x equation:

20=16x*9x

We move all terms to the left:

20-(16x*9x)=0

We add all the numbers together, and all the variables

-(+16x*9x)+20=0

We get rid of parentheses

-16x*9x+20=0

Wy multiply elements

-144x^2+20=0

a = -144; b = 0; c = +20;
Δ = b2-4ac
Δ = 02-4·(-144)·20
Δ = 11520
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:

$\sqrt{\Delta}=\sqrt{11520}=\sqrt{2304*5}=\sqrt{2304}*\sqrt{5}=48\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-48\sqrt{5}}{2*-144}=\frac{0-48\sqrt{5}}{-288}
=-\frac{48\sqrt{5}}{-288}
=-\frac{\sqrt{5}}{-6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+48\sqrt{5}}{2*-144}=\frac{0+48\sqrt{5}}{-288}
=\frac{48\sqrt{5}}{-288}
=\frac{\sqrt{5}}{-6}
$