Question

đơn giản biểu thức khi bỏ ngoặc

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

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

Answer 1

-a-(b-a-c)

=-a-b+a+c

=[-a+a]-b+c

=0-b+c

=-b+c

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

=-a+c-a+b-c

=0+0+b

=b

b-(b+a-c)

=b-b-a+c

=0-a+c

=-a+c

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

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

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

=0+0-b-b

=0-b-b

=-b-b

Answer 2

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

= -a - b + a + c

= ( -a + a ) -b + c

= 0 - b + c

= -b + c

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

= -a + c - a + b - c

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

= 2 . ( -a ) + b

c) b - ( b + a - c )

= b - b - a + c

= 0 - a + c

= -a + c

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

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

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

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

= 0 + 2 . ( -b ) + 0

= 2 . ( -b )