Question

Bỏ dấu ngoặc rồi thu gon :

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

Answer 1

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

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

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

= a - 2b + 0

= a - 2b

Answer 2

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

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

= a - 2b