What is this math answer

Is a positive integer raised to a negative power always positive

Tim's phone service charges $26.39 plus an additional $0.21 for each text message sent per month. if tim's phone bill was $31.64, which equation could be used to find how many text messages, x, tim sent last month?

For what type of equity loan are you lent a lump sum, which is to be paid within a certain period of time? a. a line of credit b. equity c. a second mortgage d. an amortization