Question

Bỏ dấu ngoặc rồi thu gọn :

A= ( a - b) - ( a - b -c ) - ( 2a + c - a)

Answer 1

A= ( a - b) - ( a - b -c ) - ( 2a + c - a)

\(=a-b-a+b+a-2a-c+a\)

\(=\left(a-a+a+a-2a\right)+\left(-b+b\right)+c\)

\(=\left(2a-2a\right)+c\)

\(=c\)

Answer 2

A = (a - b) - (a - b - c) - (2a + c - a)

\(=a-b-a+b+c-2a-c+a\)

\(=\left(a-a+a+a-2a\right)+\left(-b+b\right)+c\)

\(=\left(2a-2a\right)+0+c\)

\(=c\)

Answer 3

A= (a-b) - (a-b-c) - (2a+c-a)

A= a-b-a+b+c-2a-c+a

A= -a