Ineed to find out how to do #17. i learned once last semester but completely forgot, and i can't find how to do it again.

Because the sum of the lengths of any two sides must be greater than the third side we can say...

15+x>23

x>8

We can also say if x was the longest side...

15+23>x

x<38  from these to inequalities we can see that:

8<x<38

and the other two sides equal 38

So the range of possible perimeters is

46<p<76 or if you prefer...

p=(46,76)