How to prove -(a+b) = (-a)+ (-b)
First of all, note that `-(a+b)` is equivalent to `-1*(a +b)` .
By the distributive property of multiplication, we have:
`(-1*a) + (-1*b)`
which can be simplified/written as:
`(-a) + (-b)` which is our desired expression.
`-(a+b) = -a - b = -a + (-b) = (-a) + (-b)` again, the desired expression.