Question

2/ Đơn giản các biểu thức

a/ -(a-c)-(a-b+c)

b/ b-(b+a-c)

c/ -(a-b+c)-(a+b+c)

Answer 1

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

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

\(=b\)

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

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

\(=-a+c\)

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

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

\(=-2a-2c\)

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

Answer 2

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

= - a + c - a + b - c

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

= 0 + 0 + b

= b

b ) b - ( b + a - c )

= b - b - a + c

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

= 0 + ( - a ) + c

= ( - a ) + c

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

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

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

= ( - 2a ) + 0 + ( - 2c )

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

= - 2 ( a + c )