9x(x+1)=88

Solution for 9x(x+1)=88 equation:

9x(x+1)=88

We move all terms to the left:

9x(x+1)-(88)=0

We multiply parentheses

9x^2+9x-88=0

a = 9; b = 9; c = -88;
Δ = b2-4ac
Δ = 92-4·9·(-88)
Δ = 3249
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3249}=57$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-57}{2*9}=\frac{-66}{18}
=-3+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+57}{2*9}=\frac{48}{18}
=2+2/3
$