If |x - y| = 4, |y - z| = 5, and |z - w| = 7, what is the smallest possible value of |x - w|?
+9519 That means \(\begin{cases}x - y = \pm4 \\y - z = \pm5 \\ z - w = \pm7\end{cases}\)
Let \(a = x-y, b = y- z, c = z- w\)
\(x - w = a + b + c\)
We can interpret the question as finding the minimum sum over a, b and c.
By trying all 8 possible combinations, we get the smallest possible value to be |4 + 5 + (-7)| = 2
