1/ Đơn giản biểu thức sau khi bỏ dấu ngoặc:
a/ (a+b-c)-(b-c+d)
a+b+c-b+c-d
b/ -(a-b+c)+(a-b+d)
-a+b-c+a-b+d
c/ (a+b)-(-a+b-c)
a+b+a-b+c
d/ -(a+b)+(a+b+c)
-a-b+a+b+c
e/ (a-b+c)-(a-b+c)
a+b+c-a+b-c
f/ -(a-b-c)+(a-b-c)
-a+b+b+a-b-c
a/ (a+b-c)-(b-c+d) = a+b-c-b+c-d =a+d
b/ -(a-b+c)+(a-b+d)=-a+b-c+a-b+d=c+d
c/ (a+b)-(-a+b-c)=a+b+a-b+c=2a+c
d/ -(a+b)+(a+b+c)=-a-b+a+b+c=c
e/ (a-b+c)-(a-b+c)=a-b+c-a+b-c=0
f/ -(a-b-c)+(a-b-c)=-a+b+c+a-b-c=0
a/ (a+b-c)-(b-c+d) = a+b-c-b+c-d = (b-b)+(-c+c)+a-d = a-d
b/ -(a-b+c)+(a-b+d) = -a+b-c+a-b+d = (-a+a)+(b-b)+d-c = d-c
c/
a/ (a+b+c)-(b-c+d)
= a+b+c-b+c-d
=(b-b)+(c-c)+(a-d)
=a-d
b/ -(a+b-c)-(a-b+d)
= -a-b+c-a+b-d
=(b-b)+(-a+a)+(d-c)
=d-c
c/(a+b)-(-a+b-c)
=a+b-a-b+c
=(a+a)+(b-b)-c
=2a-c
d/ -(a+b)+(a+b+c)
= -a-b+a+b+c
=(-a+a)+(b-b)+c
=c
e/(a-b+c)-(a-b+c)
=a-b+c-a+b-c
=(a-a)+(c-c)+(b+b)
=2b
f/ -(a-b-c)+(a-b-c)
=-a+b+c+a-b-c
=(a+a)+(b+b)+(c-c)
=2a+2b