Question

Cho biểu thức : A= (-a+b-c)-(-a-b-c)
Rút gọn A

Answer 1

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

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

A=0+2b+0=2b

Answer 2

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

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

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

= 0 + 2b + 0

= 2b

Answer 3

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

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

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

\(=0+0+b+b\)

\(=b+b=2b\)