Find the period, range, and amplitude of the cosine function y=3cos x

What is this equation in point-slope form?

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x

What term makes it inconsistent y=2x - 4 ?