Please help i am being timed i beg you please help

Simplify a7/a4 a) 1/a3 b)-a/a2 c)a4/a3 d)a3

Geometry - finding area of regular polygons and sectors (check my math, i can’t find the error)

Aprobability experiment is conducted in which the sample space of the experiment is s={7,8,9,10,11,12,13,14,15,16,17,18}, event f={7,8,9,10,11,12}, and event g={11,12,13,14}. assume that each outcome is equally likely. list the outcomes in f or g. find p(f or g) by counting the number of outcomes in f or g. determine p(f or g) using the general addition rule.