(a) Subtract `4a-7ab+3b+12` from `12a-9ab+5b-3`
(b) Subtract `3xy+5yz-7zx` from `5xy-2yz-2zx+10xyz`
(c) Subtract `4p^2q-3pq+5pq^2-8p+7q-10` from `18-3p-11q+5pq-2pq^2+5p^2q`

Explanation

(a) `12a - 9ab + 5b - 3-(4a - 7ab + 3b + 12)`

`= 12a - 4a - 9ab+ 7ab + 5b -3b -3 -12`

`= 8a - 2ab + 2b -15`

(b) `5xy - 2yz-2zx + 10xyz - (3xy + 5yz- 7zx)`

`= 2xy -7yz+5zx + 10zxy`

(c) `18 - 3p - 11q + 5pq - 2pq^2 + 5p^2q-(4p^2q - 3pq + 5pq^2 - 8p+7q-10)`

`= 28 + 5p - 18q + 5pq - 7pq^2 + p^2q + 3pq`

answer