Question

12x2 + 9x2 =
do you add the exponents or do they stay the same

Answer 1

no for 2 reasons

Answer 2

so its
21x2

Answer 3

1 never add exponents in addition.
2 you can add exponents if the bases are the same.

not only are the bases not the same (2) but it is not even multiplication

Answer 4

yup :D

Answer 5

You don't add exponents because x^2 factors out:
12x^2 + 9x^2 = (12 + 9)x^2 = 21x^2

Answer 6

9x + 8x =
like is this one would it be just 17x

Answer 7

exactly