Ok -7-7=-14 because your subtracting a negative with a negative and then it will be a negative then if you multiply a negative and a negative it will be a positive

Sounds like that to me but that is symbolically showing of that's what your teacher means as mathematical sentence
EQUIVALENT WOULD BE THE ANSWER
You can use an input table x is the input and y is the output.
3(x) (y)7
3(1)=3 (3)7=21
........................................
so on