Question

What is the answer to this -30 +{-9}

Answer 1

`-39`

Explanation:

1) Use this rule:
`-a-b=-(a+b)`

`-(30+9)`

2) Use the alogrithm method.

3 0

+ 9

---------

3 9

3) After simplification, we have:

`-(30+9)=-39`

4) Therefore,
`-30 - 9 = -39`

`-39`

Answer 2

-39

Explanation:

Negative+Negative=Negative

Positive+Positive=Positive