Question

Rút gọn các biểu thức sau:

a) A=(a-b)+(a+b-c)-(a-b-c)

b) B=(a-b)-(b-c)+(c-a)-(a-b-c)

c) C=(-a+b+c)-(a-b+c)-(-a+b-c)

Giúp mk với^^

Answer 1

a) A=(a-b)+(a+b-c)-(a-b-c)=a+b

b) B=(a-b)-(b-c)+(c-a)-(a-b-c)=-a-b+3c

c) C=(-a+b+c)-(a-b+c)-(-a+b-c)=-a+b+c

Answer 2

A = ( a - b ) + ( a + b - c ) - ( a - b - c )

A = a - b + a + b - c - a + b + c

A = a + b 

B = ( a - b ) - ( b - c ) + ( c - a ) - ( a - b - c )

B = a - b - b + c + c - a - a + b + c

B = -a - b + 3c

C = ( -a + b + c ) - ( a - b + c ) - ( -a + b - c )

C = -a + b + c - a + b - c + a - b + c

C = -a + b + c

Answer 3

a, \(A=\left(a-b\right)+\left(a+b-c\right)-\left(a-b-c\right)\)

\(=a-b+a+b-c-a+b+c=a+b\)

b, \(B=\left(a-b\right)-\left(b-c\right)+\left(c-a\right)-\left(a-b-c\right)\)

\(=a-b-b+c+c-a-a+b+c=-a-b+3c\)

c, \(C=\left(-a+b+c\right)-\left(a-b+c\right)-\left(-a+b-c\right)\)

\(=-a+b+c-a+b-c+a-b+c=-a+b+c\)