-3 -0 = 0,is this correct,Thank you for yhe help

Nope. Please try again.

-3 -0= -3 is this correct?

Yes. When you add or subtract 0, the original number doesn't change.

-7.14-(10)= -2.59,is this the correct way to solve this problem?

No.

This is the same as -7.14 + (-10)

If you owe your friend $7.14 and then borrow another ten dollars from him, how much do you now owe?

17.14

Right.

-7.14-(10)= -17.14