Which set of ordered pairs represents a function? {(2, –2), (1, 5), (-2, 2), (1, –3), (8, –1)}

{(-3, –1), (-7, 1), (–6, –1), (-8, 1), (2, –1)}

{(1, 8), (5, 2), (2, –5), (1, –3), (–2, 9)}

{(–3, 1), (6, 3), (4, 2), (6, –3), (1, –1)}

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b