Verified answer

1) 2(a + b) = 2 * a + 2 * b = 2a + 2b

2) (3 - b) * 5 = 3 * 5 - b * 5 = 15 - 5b

3) 6m(7n + 8p) = 6m * 7n + 6m * 8p = 42mn + 48mp