X2=16-y

Solution for X2=16-y equation:

X2=16-X

We move all terms to the left:

X2-(16-X)=0

We add all the numbers together, and all the variables

X2-(-1X+16)=0

We add all the numbers together, and all the variables

X^2-(-1X+16)=0

We get rid of parentheses

X^2+1X-16=0

We add all the numbers together, and all the variables

X^2+X-16=0

a = 1; b = 1; c = -16;
Δ = b2-4ac
Δ = 12-4·1·(-16)
Δ = 65
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{-(1)-\sqrt{65}}{2*1}=\frac{-1-\sqrt{65}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{65}}{2*1}=\frac{-1+\sqrt{65}}{2}
$