If sin a = 7/25, cos a = 24/25, sin b = 3/5 and cos b= 4/5, find cos (a-b)

Find the indicated value, where g(t) = t^2-t and f(x)= 1+x a. -2 b. 0 c. 2 d. 8

Aman steps out of a plane at a height of 4,000m above the ground falls 2,000m very quickly and then opens his parachute and slowly falls the remaining 2000m to the ground what height above the ground would be the best choice for a reference point

Can someone me with my hwplz(only the circled ones)