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