3x(x+5)=3x+35+20

Solution for 3x(x+5)=3x+35+20 equation:

3x(x+5)=3x+35+20

We move all terms to the left:

3x(x+5)-(3x+35+20)=0

We add all the numbers together, and all the variables

3x(x+5)-(3x+55)=0

We multiply parentheses

3x^2+15x-(3x+55)=0

We get rid of parentheses

3x^2+15x-3x-55=0

We add all the numbers together, and all the variables

3x^2+12x-55=0

a = 3; b = 12; c = -55;
Δ = b2-4ac
Δ = 122-4·3·(-55)
Δ = 804
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:

$\sqrt{\Delta}=\sqrt{804}=\sqrt{4*201}=\sqrt{4}*\sqrt{201}=2\sqrt{201}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-2\sqrt{201}}{2*3}=\frac{-12-2\sqrt{201}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+2\sqrt{201}}{2*3}=\frac{-12+2\sqrt{201}}{6}
$