a=(1,2,3,4) b=(5,6,7,8) c=(9,10,11,12) and the mappings f: a:b and g: b:c

determine the elements of
i)b under g
ii)a under f
iii)a under gof i.e followed by by g

and f

i) b under g = (6,7,8,9)
ii) a under f = (5,6,7,8)
iii) a under gof = (10,11,12,13)