Answer:
r = 0.5
Step-by-step explanation:
First you need to isolate the r variable.
7r + 21 = 49r
-7r -7r
21 = 42r
Then Divide both sides by 42
0.5 = r
Now check your answer by inserting it back into the original equation.
7(0.5) + 21 = 49(0.5)
3.5 + 21 = 24.5
24.5 = 24.5
The equation is true so r = 0.5
