Answer:
Correct answer is A
Step-by-step explanation:
Is there any other part of this question that I am missing? It would be great if you could include more information on the problem.
Thank you!
Sometimes it will, and sometimes it won't.
I reason as follows:
(21 + x) + (30 + 2x) = 51 + 3x has an 'x' term
(42 + x) + (30 - x) = 72 has no 'x' term.