a) (10 pts). Using a decoder and external gates, design the combinational circuit defined by the following three Boolean functions: F1(x,y,z)=(y+x)zF2(x,y,z)=yz+xy+yzF3(x,y,z)=xz+xy b) (5 pts). Implement F (A, B, C, D) =(1,3,4,5,7,9,12,13,14,15) using 41 Mux