(x+3)(x+26)=360

Solution for (x+3)(x+26)=360 equation:

(x+3)(x+26)=360

We move all terms to the left:

(x+3)(x+26)-(360)=0

We multiply parentheses ..

(+x^2+26x+3x+78)-360=0

We get rid of parentheses

x^2+26x+3x+78-360=0

We add all the numbers together, and all the variables

x^2+29x-282=0

a = 1; b = 29; c = -282;
Δ = b2-4ac
Δ = 292-4·1·(-282)
Δ = 1969
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{1969}}{2*1}=\frac{-29-\sqrt{1969}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(29)+\sqrt{1969}}{2*1}=\frac{-29+\sqrt{1969}}{2}
$