The sum:
[tex]-a-b+a-b=-2b[/tex]
The diff:
[tex]-a-b-a+b=-2a[/tex]
Hope this helps.
Answer:
Sum= - 2b and diffrence = - 2a
Step-by-step explanation:
Since,we have two expressions - a-b and a-b
Sum=(-a-b) +(a-b) =-a-b+a-b=-2a
Since, - a+a=0 and - b-b=-2b
Diffrence =(-a-b) - (a-b) =-a-b-a+b=-2a
Since,-b+b=0 and - a-a=-2a
Hence the sum and difference of the given expression are - 2b and - 2a respectively.