9x^2+45x-36=0

Solution for 9x^2+45x-36=0 equation:

9x^2+45x-36=0

a = 9; b = 45; c = -36;
Δ = b2-4ac
Δ = 452-4·9·(-36)
Δ = 3321
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3321}=\sqrt{81*41}=\sqrt{81}*\sqrt{41}=9\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-9\sqrt{41}}{2*9}=\frac{-45-9\sqrt{41}}{18}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+9\sqrt{41}}{2*9}=\frac{-45+9\sqrt{41}}{18}
$