Respuesta :

Answer:

4(7a + 3b) = 28a + 12b

Step-by-step explanation:

The sum of 7a and 3b: 7a + 3b

4 times the sum of 7a and 3b: 4(7a + 3b)

Expanding this out:

4(7a + 3b) = 28a + 12b