(X+10)(x+5)=6

Solution for (X+10)(x+5)=6 equation:

(X+10)(X+5)=6

We move all terms to the left:

(X+10)(X+5)-(6)=0

We multiply parentheses ..

(+X^2+5X+10X+50)-6=0

We get rid of parentheses

X^2+5X+10X+50-6=0

We add all the numbers together, and all the variables

X^2+15X+44=0

a = 1; b = 15; c = +44;
Δ = b2-4ac
Δ = 152-4·1·44
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-7}{2*1}=\frac{-22}{2}
=-11
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+7}{2*1}=\frac{-8}{2}
=-4
$