A number is chosen at random from 1 to 25 find the probability of selecting a composite number

On a piece of paper graph f(x)=5•(0.4)^x

Find an equation for the linear function which has slope -10 and x-intercept -7

Steve wants to develop a way to find the total cost of any item including sales tax. the sales tax in his city is 6%. his friend jenna writes the expression x + 6x where x is the cost of the item. explain whether her expression is correct based on the situation.