Help 15 points brainliest to whoever is right (ONLY IF YOU'RE RIGHT)

Can someone answer this question? : )

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

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