Answer:
#7.
The domain is {-3,0,4}
the range is {-5,0,1,7}
not a function
#8
D={3,6,12,18}
R={5,7,9,10}
not a function
Explanation:
First, 7.
the domain is the all of the x values, in numerical order, listed once, even if it repeats.
D={-3,0,4} (notice how -3 is listed twice; despite that, we only list it once)
the range is all of the y values, in numerical order, listed once, even if the numbers repeat
R={-5,0,1,7}
A function can have the range (y values) repeat, however, the domain (x values) cannot repeat.
Therefore, this is not a function, since -3 is listed twice.
For 8.
The domain, can be listed as
D={3,6,12,18}
And the range as
R={5,7,9,10}
Notice how it says that if 6 is the input (x), the output (y) can be 5 or 10. Since we said the domain CANNOT repeat, this isn't a function.
Hope this helps!