Respuesta :

9514 1404 393

Answer:

  (b)  ±4

Step-by-step explanation:

  4r^2 -5 = 59 . . . . given

  4r^2 = 64 . . . . . . . add 5

  r^2 = 16 . . . . . . . . . divide by 4

  r = ±4 . . . . . . . . . . . take the square root