Answer:
-4a + 16b -12c -12d
Step-by-step explanation:
Given: From 4a + 7b - 12c subtract 8a - 9b + 12d.
We are given two algebraic expression. We can add/subtract only the like terms.
(4a + 7b -12c) - (8a -9b +12d)
Now we have distribute the negative sign inside the second expression (8a -9b +12b). If we do, the sign changes.
4a + 7b -12c -8a + 9b -12d [Sign rule: -(-) = +; -(+) = -]
Now we can combine the like terms
= (4a - 8a) +(7b + 9b) -12c -12d
= -4a + 16b -12c -12d
