Which function is equal to the SLOPE of the terminal side of an angle in the unit circle? please help no links please

Determine whether the quadrilateral below is a parallelogram. justify/explain your answer (this means back it up! give specific information that supports your decision. writing just "yes" or "no" will result in no credit.)

When using the linear combination metho e linear combination method to solve a system of linear equations, the four options are:

The graph shown is the graph of which function?