Question

Find the sum and the difference of the following expressions.

a-b and a+b

The sum is_____, The difference is_____.

Answer 1

Sum :
a-b+(a+b)
a+a-b+b=2a

Difference:
a-b-(a+b)
a-b-a-b
-2b

Answer 2

sum=2a

diff.=-2b

Explanation:

a-b+a+b=

2a

a-b-a-b=-2b