Respuesta :

fatpanda15

They failed to multiply 4 to both terms. The correct answer would be,

8b - 20

himikoyumenomagic

4(2b-) is another way of saying  (4 times 2b) plus (4 times -5). The friend mistake is by not multiplying the 5 in the parentheses. So the correct answer would be: 8b - 20