John participated in a science contest. he received 3 points for each correct answer but lost 2 points for each incorrect answer. after answering 50 questions, john's score was 95 points. how many questions did john answer incorrectly?

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