Answer
a) $4$ b) $5$
c) $-1$ and d) $-2$
Work Step by Step
a) $g(f(-1))=g(1)=4$ (from graph )
b) $g(f(0))=g(0)=5$ (from graph )
c) $f(g(-1))=f(3)=-1$ (from graph )
d) $f(g(4))=f(2)=-2$ (from graph )
Hence, a) $4$ b) $5$
c) $-1$ and d) $-2$