(x+8)(x+7)=112

Solution for (x+8)(x+7)=112 equation:

(x+8)(x+7)=112

We move all terms to the left:

(x+8)(x+7)-(112)=0

We multiply parentheses ..

(+x^2+7x+8x+56)-112=0

We get rid of parentheses

x^2+7x+8x+56-112=0

We add all the numbers together, and all the variables

x^2+15x-56=0

a = 1; b = 15; c = -56;
Δ = b2-4ac
Δ = 152-4·1·(-56)
Δ = 449
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{-(15)-\sqrt{449}}{2*1}=\frac{-15-\sqrt{449}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{449}}{2*1}=\frac{-15+\sqrt{449}}{2}
$