It would be B because-2 is x and 4 is y
Well for 5 movies, you do f(5) which is 32. So take 12 away from that because she already has 12, means that she still needs $20.
The two friends will be 150 miles apart, when the sum of the distances covered by the them is 150 miles.
distance = speed x time.
Let the time covered when they are 150 miles apart be x, then:
40x + 35x = 150
75x = 150
x = 150/75 = 2.
Therefore, the two friends will be 150 miles apart in 2 hours.
We are to verify the identity:
cos(α-B)-cos(α+B) = 2 sinα sinβ
Left hand side = cos(α - B)-cos(α + B)
= cosα cosβ + sinα sinB - (cosα cosB - sinα sinβ)
= cosα cosβ + sinα sinB - cosα cosB + sinα sinβ)
= sinα sinβ + sinα sinβ
= 2 sinα sinβ
= Right Hand side
