x^2+y=16

To solve this equation, first subtract 16 from both sides to get x^2 + y - 16 = 0. Then factor the left side to get (x + 4)(x - 4) = 0. Finally, set each factor equal to 0 and solve for x:

x + 4 = 0
x = -4

x - 4 = 0
x = 4