144=(9+x)(8+x)

Solution for 144=(9+x)(8+x) equation:

144=(9+x)(8+x)

We move all terms to the left:

144-((9+x)(8+x))=0

We add all the numbers together, and all the variables

-((x+9)(x+8))+144=0

We multiply parentheses ..

-((+x^2+8x+9x+72))+144=0


We calculate terms in parentheses: -((+x^2+8x+9x+72)), so:

(+x^2+8x+9x+72)

We get rid of parentheses

x^2+8x+9x+72

We add all the numbers together, and all the variables

x^2+17x+72

Back to the equation:

-(x^2+17x+72)


We get rid of parentheses

-x^2-17x-72+144=0

We add all the numbers together, and all the variables

-1x^2-17x+72=0

a = -1; b = -17; c = +72;
Δ = b2-4ac
Δ = -172-4·(-1)·72
Δ = 577
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{-(-17)-\sqrt{577}}{2*-1}=\frac{17-\sqrt{577}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+\sqrt{577}}{2*-1}=\frac{17+\sqrt{577}}{-2}
$