Can you answer this question and explain it to me? ? it's due ! ☹️☹️

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

Prove that quadrilateral is a rhombus.

M the table below represents a linear function f(x) and the equation represents a function g(x): x f(x)−1 −50 −11 3g(x)g(x) = 2x − 7part a: write a sentence to compare the slope of the two functions and show the steps you used to determine the slope of f(x) and g(x). (6 points)part b: which function has a greater y-intercept? justify your answer. (4 points)