Can someone please do this for me I am confused

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

Acomputer store bought a program at a cost of $10 and sold it for $13. find the percent markup

Angle xyz is formed by segments xy and yz on the coordinate grid below: a coordinate plane is shown. angle xyz has endpoints at 3 comma negative 1 and 6 negative 2 and 3 comma negative 3 and measures 36.87 degrees. angle xyz is rotated 270 degrees counterclockwise about the origin to form angle x′y′z′. which statement shows the measure of angle x′y′z′?