Check the picture below.
[tex]\stackrel{parent}{f(x)=x}\qquad \qquad \stackrel{transformed}{\stackrel{A}{4}(\stackrel{B}{1} x\stackrel{C}{+7})+\stackrel{D}{0}}\qquad \implies 4(x+7)[/tex]
is not really a stretch per se, more like a shrinkage, by a factor of 4 and moves to the left by 7