Respuesta :

Answer:

r = 8

Step-by-step explanation:

Solve for r:

r + 4 = 12

Subtract 4 from both sides:

r + (4 - 4) = 12 - 4

4 - 4 = 0:

r = 12 - 4

12 - 4 = 8:

Answer: r = 8