Respuesta :

kaylalg04
Answer: f= 3/4

Step 1: 8 + (4 x 1) + (4 x -3f) = 21

Step 2: 8 + 4 – 12f = 21

Step 3: 12 – 12f = 21

Step 4: 12 – 12f = 21
– 12 –12

Step 5: -12f = 9

Step 6: -12f /12 = 9/12

Step 7: 9/12 = 3/4

Step 8: f = 3/4