16+(22+a) = (16+22)+a which property is this

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?

Let f(x)=2x and g(x)=2x. graph the functions on the same coordinate plane. what are the solutions to the equation f(x)=g(x) ?me asap

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?