Answer:
A
Step-by-step explanation:
The measure of angle D can be found using the Interior Angle Sum of a Triangle.
The angles of a triangle add to 180. This means:
90 + 21 + x = 180.
111 + x = 180
x = 69
The solution is A.
Angle B is smaller than Angle D which means CD will be smaller than BC.
 
        
             
        
        
        
(x^2) - 16 / x+4 = (x-4)(x+4) / (x+4) = x-4, x not equal to -4
D is the answer.
 
        
             
        
        
        
 the number of elements in the union of the A sets is:5(30)−rAwhere r is the number of repeats.Likewise the number of elements in the B sets is:3n−rB
Each element in the union (in S) is repeated 10 times in A, which means if x was the real number of elements in A (not counting repeats) then 9 out of those 10 should be thrown away, or 9x.  Likewise on the B side, 8x of those elements should be thrown away. so now we have:150−9x=3n−8x⟺150−x=3n⟺50−x3=n
Now, to figure out what x is, we need to use the fact that the union of a group of sets contains every member of each set.  if every element in S is repeated 10 times, that means every element in the union of the A's is repeated 10 times.  This means that:150 /10=15is the number of elements in the the A's without repeats counted (same for the Bs as well).So now we have:50−15 /3=n⟺n=45
        
             
        
        
        
Answer: 
The answer is 120, 80, 100, 180, 40, 0, 240
Step-by-step explanation:
In this situation, quadrupling means to times everything (everything which is 30, 20, 25, 45, 10, 0, 60) by 4, which will give you 120, 80 ,100 ,180, 40, 0, 240