Find the value of r in(4,r) (r,3) so that the slope of the line containing them is 0

Rewrite the following without an exponent. (5/8)-1

Find dy/dx using implicit differentiation ln(20+e^xy)=y

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning