Question

Which does not represent y as a function of x?
x = y^2 + 2
y = x^2 + 2
x = y + 8
y = -x + 8
Need help :/

Answer 1

x = y^2 + 2
The same x value such as x = 3 can produce two different y values:
When x = 3, 3 = y^2 + 2
y^2 = 1
y = -1, +1.
The same x gives two different y values.
It fails the vertical line text and therefore it is not a function.