2x^2+8=9x

Solution for 2x^2+8=9x equation:

2x^2+8=9x

We move all terms to the left:

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

a = 2; b = -9; c = +8;
Δ = b2-4ac
Δ = -92-4·2·8
Δ = 17
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{-(-9)-\sqrt{17}}{2*2}=\frac{9-\sqrt{17}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+\sqrt{17}}{2*2}=\frac{9+\sqrt{17}}{4}
$