x^2+3x(x-2)=5

Solution for x^2+3x(x-2)=5 equation:

x^2+3x(x-2)=5

We move all terms to the left:

x^2+3x(x-2)-(5)=0

We multiply parentheses

x^2+3x^2-6x-5=0

We add all the numbers together, and all the variables

4x^2-6x-5=0

a = 4; b = -6; c = -5;
Δ = b2-4ac
Δ = -62-4·4·(-5)
Δ = 116
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:

$\sqrt{\Delta}=\sqrt{116}=\sqrt{4*29}=\sqrt{4}*\sqrt{29}=2\sqrt{29}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-2\sqrt{29}}{2*4}=\frac{6-2\sqrt{29}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+2\sqrt{29}}{2*4}=\frac{6+2\sqrt{29}}{8}
$