I need help with this problem please explain it good cause I'm rlly confused on how to do like I know how to solve the actual equations like ik how to get -7 and 12 but I don't know how to answer it if that makes sense​

I need help with this problem please explain it good cause Im rlly confused on how to do like I know how to solve the actual equations like ik how to get 7 and class=