If 40/11 gives you 3.6363636364 on a calculator, how would it be expressed as an exact answer

What two consecutive odd integers have a sum of -28

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?

What is the value of n in the equation -1/2(2n+4)+6=-9+4(2n+1)