(3x+15)(x+2)=2

Solution for (3x+15)(x+2)=2 equation:

(3x+15)(x+2)=2

We move all terms to the left:

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

We multiply parentheses ..

(+3x^2+6x+15x+30)-2=0

We get rid of parentheses

3x^2+6x+15x+30-2=0

We add all the numbers together, and all the variables

3x^2+21x+28=0

a = 3; b = 21; c = +28;
Δ = b2-4ac
Δ = 212-4·3·28
Δ = 105
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-\sqrt{105}}{2*3}=\frac{-21-\sqrt{105}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+\sqrt{105}}{2*3}=\frac{-21+\sqrt{105}}{6}
$