Question

12x² + 9x² = A. 21x²² B. 21x C. 22x² D. 22xA

Answer 1

Answer: A (if it's just a typo)   or   $21x^{2}$

Step-by-step explanation:

Since it's the same variable and same exponent, you just need to add the whole numbers and put the same variable and exponent.

12 + 9 = 21

$21x^{2}$

Answer 2

Answer:

21x²

Step-by-step explanation:

hopefully A is a typo