NEED HELP ASAP What type of function is this: y=.7X ?

1:Quadratic

2:Exponential growth

3:Exponential Decay

4:linear

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?

The sales totals at macy's food store have increased exponentially over the months. which of these best shows the sales in the first three months?

The lengths of two sides of a right triangle are given. find the length of the third side. round to the nearest tenth if necessary. a) y = 12/5x + 39/5 b) y = 5/12x + 5/39 c) y = 12/5x - 39/5 d) y = 5/12x - 5/39