In this question, you would be solving the expression by combining like terms.
Solve:
(5a + 3b - 6c) - (20 - 4b + 13c)
Distribute the negative to the variables inside the parenthesis.
5a + 3b - 6c - 20 + 4b - 13c
Combine like terms.
5a + 7b - 6c - 20 - 13c
5a + 7b - 19c - 20
You can't combine anymore like terms now, so your answer would be 5a + 7b - 19c - 20
Answer:
5a + 7b - 19c - 20