1) 14а-21b-504+72a-63a-45b=23a-66b-504
2) 23m-69n-27m+21n+6m-7n=2m-55n
3) -72x-108y-180+66x-72y-80=-6x-180y-260
4) 99p-30p+18q+135p-756-594p=-390p+18q-756
1) 14а-21b-504+72a-63a-45b=23a-66b-504
2) 23m-69n-27m+21n+6m-7n=2m-55n
3) -72x-108y-180+66x-72y-80=-6x-180y-260
4) 99p-30p+18q+135p-756-594p=-390p+18q-756