Which of the following describes the graph of w(x)=(x-2)2

In the field of thermodynamics, rankine is the unit used to measure temperature. one can convert temperature from celsius into rankine using the formula c= r/1.8 - 273, what is the temperature in celcius corresponding to r degrees rankine.

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

Which one is the correct answer, and why?