when you subtract a negative number from another negative number is it positive or negative

It depends upon the relative sizes of the numbers:

It could be negative:  -6 - (-2)   =  -6 + 2    =  -4

If could be zero:        -6 - (-6)   =  -6 + 6    =  0

It could be positive:  -6 - (-10)  =  -6 + 10  =  4

If you subtract a positive number from a negative number, the answer will always be negative.

It's a negative number.

Try using a number line. You're at a negative number, and you're moving backward. Your number is still negative.

Hope this helps.