3x(x+2)=20-4x

Solution for 3x(x+2)=20-4x equation:

3x(x+2)=20-4x

We move all terms to the left:

3x(x+2)-(20-4x)=0

We add all the numbers together, and all the variables

3x(x+2)-(-4x+20)=0

We multiply parentheses

3x^2+6x-(-4x+20)=0

We get rid of parentheses

3x^2+6x+4x-20=0

We add all the numbers together, and all the variables

3x^2+10x-20=0

a = 3; b = 10; c = -20;
Δ = b2-4ac
Δ = 102-4·3·(-20)
Δ = 340
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:

$\sqrt{\Delta}=\sqrt{340}=\sqrt{4*85}=\sqrt{4}*\sqrt{85}=2\sqrt{85}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-2\sqrt{85}}{2*3}=\frac{-10-2\sqrt{85}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+2\sqrt{85}}{2*3}=\frac{-10+2\sqrt{85}}{6}
$