0.8x^2=18^2+0.2x^2

Solution for 0.8x^2=18^2+0.2x^2 equation:

0.8x^2=18^2+0.2x^2

We move all terms to the left:

0.8x^2-(18^2+0.2x^2)=0

We get rid of parentheses

0.8x^2-0.2x^2-18^2=0

We add all the numbers together, and all the variables

0.6x^2-324=0

a = 0.6; b = 0; c = -324;
Δ = b2-4ac
Δ = 02-4·0.6·(-324)
Δ = 777.6
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{777.6}}{2*0.6}=\frac{0-\sqrt{777.6}}{1.2}
=-\frac{\sqrt{}}{1.2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{777.6}}{2*0.6}=\frac{0+\sqrt{777.6}}{1.2}
=\frac{\sqrt{}}{1.2}
$