Simplify (1.5 • 10^9) - (7.8 • 10^8) expressed in scientific notation

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?

Graph the system: f(x)= 3/x-2; f(x)= 1/2x + 2

Select the graph of the solution. click until the correct graph appears. |x| = 3