A function is defined by f(x) = 2x + 1, x < 0; x², 0 ≤ x ≤ 3; 12 - x, x > 3.

Step 1. The values. $f(-2) = -3$, $f(0) = 0$, $f(2) = 4$, $f(3) = 9$, $f(5) = 7$. The sum is $17$.

Step 2. At $x = 0$. From the left, $2x + 1$ approaches $1$, but $f(0) = 0$: a jump.

Step 3. At $x = 3$. $x^2 = 9$ and $12 - 3 = 9$: no jump.