Suppose that x and y vary inversely and that y = 5 when x = 1. What is y when x = 15?

Express in the simplest form: (x^2+9x+14/x^2-49) / (3x+6/x^2+x-56)

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

Sam opened a money-market account that pays 3% simple interest. he started the account with $7,000 and made no further deposits. when he closed the account, he had earned $420 in interest. how long did he keep his account open?