The word "is" in this kind of problem typically means "=", so we know that something =-8. Since we're finding the number, we should start with the closest thing in the phrase given to that number. In this case, it's 3/4x. Finally, since we have the "14 less than", we need to add that in. Your answer is:
3/4x-14=-8. Now we can just solve!
+14 +14
3/4x=6.
*4/3 *4/3
x=8.