(-4)+(-3)-(+7)=-4-3-7=-14
(-а)+(-7b)+1/3c= -a-7b+1/3c=-3ac-21bc+1/3c
a+(2b-3c)=a+2b-3c
a-(2b+3c)=a-2b-3c
a+(b-(c-d)=b+c-d
a-((b-c)-d)=a-b+c+d
3a-(a+2b)=2(a-b)
3m-(5m-(2m-1))=3m-(5m-2m+1)=3m-(3m+1)=3m-3m-1=-1
(-4)+(-3)-(+7)=-4-3-7=-14
(-а)+(-7b)+1/3c= -a-7b+1/3c=-3ac-21bc+1/3c
a+(2b-3c)=a+2b-3c
a-(2b+3c)=a-2b-3c
a+(b-(c-d)=b+c-d
a-((b-c)-d)=a-b+c+d
3a-(a+2b)=2(a-b)
3m-(5m-(2m-1))=3m-(5m-2m+1)=3m-(3m+1)=3m-3m-1=-1