Answer:
Aida did not correctly divide by the common factor to get (4 + 8).
She should have written: (5 + 7)
It would look like this: 15 + 21 = 3(5 + 7)
This make both sides equivalent: 15 + 21 = 15 + 21 Yay!
Hope this helps!
7.2m questions
9.6m answers