The function y=2x+4 has a domain of 2, 3, 5, 7, and 8. Which number is NOT in the range of the function?

Question

A) 8

b) 12

c) 18

d) 20

e) none of the above

I would really appreciate it if someone helped me with this question.

Answer 1

The range is the y values, So if y = 2x+4

Then,

1) y = 2(2)+4 = 8

2) y = 2(3)+4 = 10

3) y = 2(5)+4 = 14

4) y = 2(7)+4 = 18

5) y = 2(8)+4 = 20

It looks like the only number above not in the range is 12

Answer 2

By substituting; 12 isn't an out-come of this formula.