Question

rút gọn a

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

 

Answer 1

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

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

=0+0+2c

=2c

Answer 2

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

Answer 3

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

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

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

= 0 + 0 + 2c

= 2c

Answer 4

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

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

= 0 + 0 + 2c

= 2c