Answer:
29ba - 7 - 5bc
Explanation:
8ab-5bc +21ba-7
The terms 8ab, 5bc, and 21ba are made up of units multiplied by each other. This means that each can be rewritten in a different order. For example,
8ab is the same as:
8ba, b8a, ab8, ba8, or a8b
We may rewrite the terms to see the ones that can be combined.
8ab-5bc +21ba-7
8ba-5bc +21ba-7
8ba+21ba-7-5bc
29ba - 7 - 5bc