(x*4)(x*3)=99

Solution for (x*4)(x*3)=99 equation:

(x*4)(x*3)=99

We move all terms to the left:

(x*4)(x*3)-(99)=0

We add all the numbers together, and all the variables

(+x*4)(+x*3)-99=0

We multiply parentheses ..

(+12x^2)-99=0

We get rid of parentheses

12x^2-99=0

a = 12; b = 0; c = -99;
Δ = b2-4ac
Δ = 02-4·12·(-99)
Δ = 4752
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:

$\sqrt{\Delta}=\sqrt{4752}=\sqrt{144*33}=\sqrt{144}*\sqrt{33}=12\sqrt{33}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-12\sqrt{33}}{2*12}=\frac{0-12\sqrt{33}}{24}
=-\frac{12\sqrt{33}}{24}
=-\frac{\sqrt{33}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+12\sqrt{33}}{2*12}=\frac{0+12\sqrt{33}}{24}
=\frac{12\sqrt{33}}{24}
=\frac{\sqrt{33}}{2}
$