Answered By Samuel L

There are several ways to solve this. The easier one is to first multiply both sides of the equation with 5r. The equation becomes 

        55 = 7r - 50

That is

         7r = 105

And finally 

           r = 15

 

Answered By Jackie C

The equation can be changed into 

11/r+10/r=21/r=7/5, then r=21*5/7=15

Answered By Roselle C

11/r =7/5-10/r --> goal is to isolate r (r)11/r =(r)7/5-(r)10/r --> first let's multiply r out, to both sides of the equation 11= 7r/5-10 --> now solve ... left side(r on top and bottom cancel each other) and right side (r on top and bottom cancel each other) 11= 7r/5-10 --> now multiply 5 to every term to eliminate the denomiator of 5 11(5)= (5)7r/5-(5)10 --> now solve this step 55= 7r-50 --> now add 50 to both side  55+50= 7r-50+50 --> solve this by adding 105 = 7r --> now divide both sides by 7, isolating r!! 105/7 = 7/7r 15 = r or r = 15