You need a right triangle correct. If you used a graph and put the points (5,12) & (11,12) it would make sense to have the next point --this(11,4)
The answer is 3.6. Hope this helps!
X is the number
when x is decreased by 18, we say 18-x
the result is 14
18-x=14
minus 18 both sides
-x=-32
times both sides by -1
x=32