如题
比如
2x - 3 (2y - 4z)
5a - 1/2 ( 4b - 6c )
怎么做啊!?
2x - 3 (2y - 4z)=2x -6y+12z
5a - 1/2 ( 4b - 6c )=5a -2b+3c
2x-3(2y-4z)=2x-6y+12z
5a-1/2(4b-6c)=5a-2b+3c