Is {(4, 8), (8, 4), (4, 12), (20, 16), (12, 16)} a function

  no

Step-by-step explanation:

Look at the first numbers of each ordered pair:

  4, 8, 4, 20, 12

If any are repeated, the relation is NOT a function. Here, 4 is repeated.

The relation is not a function.

  n=   0.0000 - 0.3750 i  

  n=   0.0000 + 0.3750 i

step-by-step explanation:

one of these should be correct

i think it is everything has to equal 180 so, if i correct 4=c. 6=d. 8=a. 7=b. and the last question would be c. because they are parallel lines and they are congruent.

step-by-step explanation:

the reason everything has to equal to 180 is because that is how it works. i'm guessing that is its rule. 4 and 8 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 6 and 7 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 60+60 is 180. so, now you have your answer