Respuesta :

miatortilla2

If r = 20, then plug 20 into the equation.

so instead of r - 9, it's 20 - 9

20 - 9 = 11
Well if you need to find out what R - 9 is and R=20 then 20-9= 11 so 11 is your answer. :)))) Super Sorry if I'm wrong. :(((