Whicth inequality is true for X=20

See attachment below and find the equivalent of tan(∠qsr)

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

The experience c-0.25c can be used to find the cost of an item on sale for 25% off which expression beloit equivalent to c-0.25c