2x(x+15)=55+x

Solution for 2x(x+15)=55+x equation:

2x(x+15)=55+x

We move all terms to the left:

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

We add all the numbers together, and all the variables

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

We multiply parentheses

2x^2+30x-(x+55)=0

We get rid of parentheses

2x^2+30x-x-55=0

We add all the numbers together, and all the variables

2x^2+29x-55=0

a = 2; b = 29; c = -55;
Δ = b2-4ac
Δ = 292-4·2·(-55)
Δ = 1281
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{-(29)-\sqrt{1281}}{2*2}=\frac{-29-\sqrt{1281}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(29)+\sqrt{1281}}{2*2}=\frac{-29+\sqrt{1281}}{4}
$