Question

bỏ dấu ngoặc rồi thu gọn biểu thức 

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

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

Answer 1

a.

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

    \(=a+b-a+b+a-c-a-c\)

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

    \(=2b-2c\)

b.

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

    \(=a+b-c+a-b+c-b-c+a-a+b+c\)

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

    \(=2a\)

Chúc bạn học tốt

Answer 2

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

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

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

A= 0 + 2b - 2c

A= 2(b-c)

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

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

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

B= 2a+0+2c

B=2(a+c)

Answer 3

Mình sai một chút phần b

Answer 4

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

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

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

=2b-2c

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

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

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

=2a