Need help now urgent because I am so confused on this problem and it’s due in 1 hour

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

Simplify 15(x - 4)(x -1)-3(x + 4)(x - 1) with steps

Rachel is studying the population of a particular bird species in a national park. she observes every 10th bird of that species that she can find in the park. her conclusion is that the birds living in the park who belong to that species generally feed on insects. rachel's sample is . based on the sample she picked, rachel's generalization is . reset next