Assignment $1$ masons gain formula

Derive the transfer function

Q$2)$ Suppose the equations given as

$x2=g_{21}{x}_1+g_{23}{x}_3$

$x_3=g_{31}{x}_1+g_{32}{x}_2+g_{33}{x}_3$

$x_4=g_{42}{x}_2+g_{43}{x}_3$

Draw the signal flow graph