2(x+3)(x+1)=x+15

Solution for 2(x+3)(x+1)=x+15 equation:

2(x+3)(x+1)=x+15

We move all terms to the left:

2(x+3)(x+1)-(x+15)=0

We get rid of parentheses

2(x+3)(x+1)-x-15=0

We multiply parentheses ..

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

We add all the numbers together, and all the variables

2(+x^2+x+3x+3)-1x-15=0

We multiply parentheses

2x^2+2x+6x-1x+6-15=0

We add all the numbers together, and all the variables

2x^2+7x-9=0

a = 2; b = 7; c = -9;
Δ = b2-4ac
Δ = 72-4·2·(-9)
Δ = 121
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{121}=11$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-11}{2*2}=\frac{-18}{4}
=-4+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+11}{2*2}=\frac{4}{4}
=1
$