Question 173930
You are spot on so far.


{{{(6-8)/(r+4)=2/3}}}


{{{(-2)/(r+4)=2/3}}}


Now, just like any other proportion, cross multiply, collect terms and solve for r:


{{{2(r+4)=-6}}}


{{{2r+8=-6}}}


{{{2r=-14}}}


{{{r=-7}}}