Idont get how u make a the subject and get a on its own can u me with all the questions even if u only know the answers too a few of them

It just means to get a by itself on one side of the equal sign. For the first equation subtract 7p from both side. The equation would then look like 3a=8-7p. After, you divide 3 from both sides and the answer for the first part would be a=8-7p/3 (8-7p will all be divided by 3). If you are having problems with the other equation I'll be happy to help.