How do you work this out? we have to make one positive and the other negative then put it on a graph correctly

The answer to Q1 along with an explanation is shown in the picture;
Having a look at all the questions, they are all essentially the same type so can all be solved similarly;
So by following the method and explanation, you should be able to do the rest of the questions.

The year before the 10s so it was like when caveman were alive