2а+3b-(3b-2а)+2а-3b-(-3а-3b)-2+3b=
2а+3b-(3b-2а)+2а-3b-(-3а-3b)-2+3b= 2а+3b-3b+2a+2a-3b+3a+3b-2+3b= =6a-6a-3b =-3b