I need help please quiz

9/10 divide by -3/15 as a mixed number

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

If p(a) = 0.70 and p(b) = 0.20, then a and b are independent events if