Answer :
g(-4)
=1/2((-4)-1)
=1/2(-5)
=-2.5
------------------------------
f(g(-4))
=f(-2.5)
=2(-2.5)+1
=-5+1
=-4
=1/2((-4)-1)
=1/2(-5)
=-2.5
------------------------------
f(g(-4))
=f(-2.5)
=2(-2.5)+1
=-5+1
=-4