Which term could be put into the blank to create a fully simplified polynomial written in standard form

Match each equation with the operation you can use to solve for the variable. subtract 10. divide by 10. divide by 5. subtract 18. multiply by 10. add 18. add 10. multiply by 5. 5 = 10p arrowright p + 10 = 18 arrowright p + 18 = 5 arrowright 5p = 10 arrowright

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

Add the fractions, and simply the result to lowest terms. 2/3 + 2/7= ?