Question 348631
 {{{r(x)= x/(x+4)}}}
 {{{ r(1/2)= (1/2)/(1/2+4)}}}
 {{{ r(1/2)=  (1/2)/(1/2+8/2) }}}
{{{ r(1/2)= (1/2)/(9/2)}}}
 {{{highlight(r(1/2)= 1/9)}}}