Below is a portion of the graph of a function, $y=u(x)$:
What is the exact value of $u(-2.72)+u(-0.81)+u(0.81)+u(2.72)$ ?
This is a graph of an odd function
An odd function has the property that f(-a) + f(a) = 0
Therefore
u(-2.72) + u(2.72) + u(-0.81) + u(0.81) =
0 + 0 =
0
+195 
