Many manufacturers use inequalities to solve production problems

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

The length of a shadow of the building is 36m. the length of the pole, which is perpendicular to the ground, is 1.9m. the length of the pole's shadow is 1.52m. what is the height of the building?

On #16 : explain how factoring a trinomial, ax^2+ bx+ c, when a does not equal 1 different from factoring a trinomial when a = 1.