Question 1008779
S is also factorable...
{{{S(x)=(x-4)(x-6)}}}, so x-intercepts are 4 and 6.  The y-intercept is for x=0, and is  24.


You can still find the vertex; because it is exactly in the middle of x=4 and x=6.  What is the middle of those?  Now what is S at that x value?  (5,-26)  is the vertex.