Answer:
3y
Explanation:
A term is a mathematical expression, in this case a number multiplied by a variable.
Like terms would mean anything that is equal to 3x.
Because 3 is a constant number, any like terms have to have the number 3 in it, so we can eliminate 5x, -2x, 7y, and x because they don't have a 3.
y is a variable which is a stand-in for an unknown number, and it can be switched out with any one variable. That means the only possible answer is 3y