Answer: B
Step-by-step explanation:
Use the formula cos(A-B) = cosA cos B + sin A sin B.
if you use the Pythagorean theorem to find the other sides of Triangle A and B and use them to find the cosine of A and B, you should get:
(4/5)(sq rt of 5/3) + (3/5)(2/3)
(4 sq rt of 5/15) + (6/15)
4 sq rt of 5 + 6/15
