At Walmart, apples cost $0.50 each, and grapefruits cost $2 each. You want to spend exactly $15. Define all unknown variables. Write an equation modeling this situation.

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