chung to
1 (a-b+c)-(a+c)=-b
2 (a+b)-(b-a)+c=2a+c
3 -(a+b-c)+(a-b-c)=-2b
4 a(b+c)-a(b+d)=a(c-d)
5 a(b-c)+a(d+c)=a(b+d)
Loga
Sinh Học lớp 12
