What is the average rate of change from -1 to 1 of the function represented by the graph?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

If i purchase a product for $79.99 and two accessories for 9.99 and 7.00 how much will i owe after taxes applies 8.75%

Johnny rode his bike to a friends house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was unable to play. what was his displacement for the total bike ride trip? what could you use as a reference point ? show the steps to solve this problem.