algebra question for my test!! 5radR -4=R+2?

Question

rad =radical i need the seps i have the answers!!

Answer 1

square both sides and you get
25(r-4) = (r+2)^2
Distribute it out and you get a quadratic equation, solve by factoring or the quad formula.
Make sure the results fit in the original question, as sometimes squaring both sides generates extraneous roots. Here we go...
25r - 100 = r^2 + 4r + 4
subtract to get everything over to one side
0 = r^2 - 21r + 104
This factors
(x-8)(x-13)
So the solutions are 8 and 13
Now make sure they work in the original question,,,
5sqrt(8-4) = 8+2
5sqrt(13-4) = 13+2
they both work.