$[10$ points$]$ Given a sorted array of numbers A$[1...$ n$],$ we would like to determine a value x such that both x and $(2$x $+17)$ are in the array. If there is$,$ print one such value x$,$ else, print that there is no such value.

$($iii$)$ Design a O $($n$)$ time, $\backslash$Theta $(1)$ extra space algorithm FINDX$-$BEST$($A$[1...$ n$])$ to solve the problem.