Can someone help me with this math homework please!

Through non-collinear points there is exactly one plane.

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

Acar loses a quarter of its value every year. it is originally worth $35,000. to the nearest dollar,how much will the car be worth in 8 years?