Answer:
B. -21a-15
Step-by-step Explanation:

They must be complementary. these 2 angles MUST equal 90 degrees because there is a right angle that is 90 degrees in the triangle already and all triangles have an angle sum of 180 degrees. the answer is complementary
Answer:
the answer is none of those it is 4/13
They both saw the same amount because 6+3 = 9 and 3+6 = 9