Rolling a 4 sided die with the numbers 1-4 on the faces of the die

Three coins are flipped. what is the probability that there will be at least two tails?

Evaluate the following expression 1/3^2

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?