I believe this would be correct.
Answer:
you are correct it is, 4a+100b
Step-by-step explanation:
I would multiply 4/7 by 5 and 3/5 by 7 to get 20/35 and 21/35. The Least Common factor is 35
5/12=10/24 and 7/8= 21/24, add those and you will get 31/24 subtract 31 from24 and get 7 your new fraction is 1 7/24 that is 5/12 + 7/8 in simplest form
