2x^2-(9x)=221

Solution for 2x^2-(9x)=221 equation:

2x^2-(9x)=221

We move all terms to the left:

2x^2-(9x)-(221)=0

a = 2; b = -9; c = -221;
Δ = b2-4ac
Δ = -92-4·2·(-221)
Δ = 1849
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1849}=43$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-43}{2*2}=\frac{-34}{4}
=-8+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+43}{2*2}=\frac{52}{4}
=13
$