Like terms means terms that have the same variable (and with the same exponent).
A) 9
x and 9
y <-- those are different variables. This is incorrect.
B) 12
ac^2 and
ac^2 <-- those are the same variables and same exponent. Correct.
C) 8
xy and 8
xz <-- different variables, incorrect.
D)
ab^2 and
x^2y <-- different variables, incorrect.
Correct answer is
