Iris wants to buy sneakers at $15 each and high heels at $30 each. Write an algebraic expression to find the total cost of the shoes if she buys x sneakers and y high heels. Write your answer in the form “ax + by” where a and b are positive or negative constants.

The table below shows the approximate masses of a dust particle and a grain of pollen. dust particle 0.000000778 g grain of pollen 0.00000000155 g the mass of a dust particle can be estimated and written in the form a × 10^b, where a = 8 and b = the mass of a grain of pollen can be estimated and written in the form a × 10^b, where a = 2 and b = based on the estimates, the mass of a dust particle is approximately blank times larger than the mass of a grain of pollen.