(3x+3)(5x+1)=1800

Solution for (3x+3)(5x+1)=1800 equation:

(3x+3)(5x+1)=1800

We move all terms to the left:

(3x+3)(5x+1)-(1800)=0

We multiply parentheses ..

(+15x^2+3x+15x+3)-1800=0

We get rid of parentheses

15x^2+3x+15x+3-1800=0

We add all the numbers together, and all the variables

15x^2+18x-1797=0

a = 15; b = 18; c = -1797;
Δ = b2-4ac
Δ = 182-4·15·(-1797)
Δ = 108144
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:

$\sqrt{\Delta}=\sqrt{108144}=\sqrt{144*751}=\sqrt{144}*\sqrt{751}=12\sqrt{751}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-12\sqrt{751}}{2*15}=\frac{-18-12\sqrt{751}}{30}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+12\sqrt{751}}{2*15}=\frac{-18+12\sqrt{751}}{30}
$