⑴-t-t-t⑵9ab-4ab+ab-7ab+5ab⑶-12x+6y-3+10x-2-y⑷5m-7n-8p+5n-9m-
5个回答

⑴-t-t-t

=-3t

⑵9ab-4ab+ab-7ab+5ab

=4ab

⑶-12x+6y-3+10x-2-y

=-2x-5y-5

⑷5m-7n-8p+5n-9m-p

=-4m-2n-9p