9x-x^2=16

Solution for 9x-x^2=16 equation:

9x-x^2=16

We move all terms to the left:

9x-x^2-(16)=0

We add all the numbers together, and all the variables

-1x^2+9x-16=0

a = -1; b = 9; c = -16;
Δ = b2-4ac
Δ = 92-4·(-1)·(-16)
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*-1}=\frac{-9-\sqrt{17}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+\sqrt{17}}{2*-1}=\frac{-9+\sqrt{17}}{-2}
$