Can someone help me?

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

Is a positive integer raised to a negative power always positive

Someone answer asap for ! michele pushes a box d meters across a floor. she uses a force f, in newtons, to push the box. she pushes the box for t seconds. the formula p = fd/t calculates the power, p, in watts, that it takes for michele to complete the task. solve the formula for d.