Question

M(x)=x+5/x+1, n(x)=x-3, what is m(n(x))?

Answer 1

Subsitute n(x) for x in M(x)

$M(n(x))=\frac{n(x)+5}{n(x)+1}=$
$M(x-3)=\frac{(x-3)+5}{(x-3)+1}=$
$M(x-3)=\frac{x-3+5}{x-3+1}=$
$M(x-3)=\frac{x+25}{x-2}=$

 I have no idea where you got $\frac{11}{x-4}$