Answer:
r = 60
Explanation:
With any equation with a variable, you want to isolate the variable to find its actual value. I'll show you a step by step:
10r - 60 = 9r
Subtract 9r from both sides:
10r - 9r - 60 = 9r - 9r
Simplify:
r - 60 = 0
Add 60 to both sides to isolate r:
r - 60 + 60 = 0 + 60
Simplify:
r = 60