Which expression is equivalent to 10n plus 81-9?

Using only odd number for numerators write two different subtraction problems that have a difference of 3/4

Frank has a devised a formula for his catering business that calculates the number of meatballs he needs to prepare. the formula is m=4a+2c, where c=number of children; m=number of meatballs; a=number of adults. how many meatballs are required for a party of 10 adults and 5 children?

Subject: geometryneed with 6 and 7