2. Is this a function? Why or why not? (12,1), (12,3), (12,5), (12,7)
A. It is not a function because 9 doesn’t map to anything.
B. It is not a function because 12 maps to more than one element of the range.
C. It is a function because only one element maps to each element of the range.
D. It is a function because each y-value maps to only one x-value.
E. It is a function because 12 maps to one element of the range.

3. Is this a function? Why or why not?
{(1, 3), (2, 4), (3, 5), (4, 7)}
A. It is not a function because 4 + 2 is not equal to 7.
B. It is not a function because (0, 0) is not included in the set of points.
C. It is not a function because the domain is not equal to the range. .
D. It is a function because all of the numbers are positive.
E. It is a function because each y-value maps to only one x-value.
F. It is a function because each x-value maps to only one y-value.

13. Find the domain of
x^2 + 1/ x + 1
A. x ≠ 1
B. x ≠ -1, 0, 1
C. x ≠ 0
D. x ≠ -1,1
E. x ≠ -1
F. x ≠ -2
14.

Find the domain of
x ¹ -2/x + 1
A. x ≠ -1
B. x ≠ 1
C. x ≠ -2
D. x ≠ -1, 1
E. x ≠ 2
F. x ≠ 0
15. Find the domain of
x^2-2x-1/ x^2-1
A. x ≠ -1
B. x ≠ 0
C. x ≠ 1
D. x ≠ 4
E. x ≠ -2
F. x ≠ -1, 1
16. Find the domain of

x^2 + 5x + 4/ x^2 + 7x + 6
A. x ≠ 4
B. x ≠ 6, -1
C. x ≠ -4
D. x ≠ -6, -1
E. x ≠ -2, -3
F. x ≠ 2, 3