Seven times a number is equal to 12 more than three times the number. find the number

A20? -foot ladder is placed against a vertical wall of a? building, with the bottom of the ladder standing on level ground 19 feet from the base of the building. how high up the wall does the ladder? reach?

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

Write the point-slope form of the line passing through (2, -12) and parallel to y=3x.