24=x*1.15*x

Solution for 24=x*1.15*x equation:

24=x*1.15x

We move all terms to the left:

24-(x*1.15x)=0

We add all the numbers together, and all the variables

-(+x*1.15x)+24=0

We get rid of parentheses

-x*1.15x+24=0

Wy multiply elements

-1x^2+24=0

a = -1; b = 0; c = +24;
Δ = b2-4ac
Δ = 02-4·(-1)·24
Δ = 96
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:

$\sqrt{\Delta}=\sqrt{96}=\sqrt{16*6}=\sqrt{16}*\sqrt{6}=4\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{6}}{2*-1}=\frac{0-4\sqrt{6}}{-2}
=-\frac{4\sqrt{6}}{-2}
=-\frac{2\sqrt{6}}{-1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{6}}{2*-1}=\frac{0+4\sqrt{6}}{-2}
=\frac{4\sqrt{6}}{-2}
=\frac{2\sqrt{6}}{-1}
$