(This is for a quiz and it’s kinda urgent so if someone could help soon that would be great!)

Identify each equation as a function or NOT a function.
y = 2/3 x + 12
y = 4
y² = 1/2x + 6
x = -3
3x + 4y = -1
(This is for a quiz and it’s kinda urgent so if someone could help soon that would be great!)