Answer:
A) 8, 15, 17.
Step-by-step explanation:
Right triangle obey the Pythagorean theorem. Thus, we choose the two smaller numbers (being the cathetus) and if after applying the P. Theorem we get the biggest of each option (the hypotenuse) that means that those numbers could be the sides of a right triangle.
The Pythagorean theorem states that: 
Thus:

Option A:
→ 17 = 17 OK!
Option B:
→ 10 ≠ 12 NO
Option C:
[/tex] →
≠ 21 NO
Option D:
→
≠ 16 NO
Answer:
34 - 31i
Step-by-step explanation:
first, distribute to get 40 - 16i - 15i + 6i^2. i^2 = -1 so 6(-1) is -6. simplify to get 34 -31i
14/18-9/18=5/18 it can't be simplified anymore
Answer:
A intersection B = ( elements which are common in both)
= ( 2,4,7,19)
A union B = ( all the elements which are either in A or in B).
= ( 2, 4, 7 , 13, 14, 19, 20 , 3, 5, 6, 10,11, 12 , 15,17 , 18 , 19 )