Answer:
Problem 1. (19/2)b + 15
Problem 2. 3/16
Explanation:
Question number 1
5/8 (16b+24) -1/2b =
= (5/8) * (16/1) * b + (5/8) * 24 - (1/2)b
= 10b + 15 - (1/2)b
= (20/2)b - (1/2)b + 15
= (19/2)b + 15
Question number 2
3/4 (16/64 + 12a) -9a =
= (3/4) * (16/64) + (3/4) * 12a - 9a
= (3 * 16)(4 * 64) + (3/4) * (12/1) * a - 9a
= (3 * 1)(4 * 4) + (3 * 12)/(4 * 1) * a - 9a
= 3/16 + (3 * 3)/(1 * 1) * a - 9a
= 3/16 + 9a - 9a
= 3/16