In surjective and injective functions is it possible for elements of the domain not to be mapped to an element of the range? if it is i have further questions. but as an example, would have a hole at 2 but still have a value at every y value. so would it be surjective?

Step-by-step explanation:

The definition of a function f from A to B, regardless to injectivity or surjectivity, is that the domain of f is A, in its entirety.

This means that if f:A→B, then for every a∈A, there is a unique b∈B such that the pair (a,b)∈f.

So the converse holds just for it to be a function from A to B.

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9