y*0.23y=2100

Solution for y*0.23y=2100 equation:

y*0.23y=2100

We move all terms to the left:

y*0.23y-(2100)=0

Wy multiply elements

0y^2-2100=0

We add all the numbers together, and all the variables

y^2-2100=0

a = 1; b = 0; c = -2100;
Δ = b2-4ac
Δ = 02-4·1·(-2100)
Δ = 8400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{8400}=\sqrt{400*21}=\sqrt{400}*\sqrt{21}=20\sqrt{21}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-20\sqrt{21}}{2*1}=\frac{0-20\sqrt{21}}{2}
=-\frac{20\sqrt{21}}{2}
=-10\sqrt{21}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+20\sqrt{21}}{2*1}=\frac{0+20\sqrt{21}}{2}
=\frac{20\sqrt{21}}{2}
=10\sqrt{21}
$