Here is the equation:
[tex]3-(-5)[/tex]
When you're subtracting a negative number from a positive number, the sign will change. The - sign will become + and the negative number becomes positive.
[tex]3- \rightarrow 3+ \\ -5 \rightarrow 5[/tex]
Here is your new equation:
[tex]3+5[/tex]
All you need to do is add 3 and 5.
[tex]3+5=8[/tex]
That means your answer is 8.