Answer:
10 + 5
Step-by-step explanation:
If you are subtracting a negative then it become adding a positive. A way to remember this is because it has matching socks.
There is 20 students. To find the answer you need to use porportionals and cross multiply.
Not really sure what you mean by compare. The only thing I can think of is the y intercept is generally a good point to start from to count the rise/run
