x^2+8.8x=72.25

Solution for x^2+8.8x=72.25 equation:

x^2+8.8x=72.25

We move all terms to the left:

x^2+8.8x-(72.25)=0

We add all the numbers together, and all the variables

x^2+8.8x-72.25=0

a = 1; b = 8.8; c = -72.25;
Δ = b2-4ac
Δ = 8.82-4·1·(-72.25)
Δ = 366.44
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{-(8.8)-\sqrt{366.44}}{2*1}=\frac{-8.8-\sqrt{366.44}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8.8)+\sqrt{366.44}}{2*1}=\frac{-8.8+\sqrt{366.44}}{2}
$