Question 599290
Plug in various values of x (start at x = 1 and increment by 1, so plug in x = 2, then x = 3, etc..) and make the following table.



<pre>
            x           y
------------------------------------
            0           23
            1           23
            2           25
            3           29
            4           35
            5           43
            6           53
            7           65
            8           79
            9           95
           10          113

</pre>


Looking at the table above, we can see that when x = 2, y = 25 (which is a composite number). So {{{x^2-x+23}}} is composite when {{{x=2}}}