To do synthetic division, you take the number from the (x+#) and place it on the outside (you'll see what I mean soon). However, it'll be the opposite of the number so in this case it'll be negative 2 instead of positive 2. Afterwards, bring down the rest of the numbers; ignore the exponents and variables.
Here's how to set the synthetic division up.
-2 | 5 -12 -36 -16
1. Bring down the 5 so that you have something to begin with.
2. Multiply 5 by -2., which is -10.
3. Add -12 and -10, which gives you -22.
4. Repeat steps; this time multiplying -22 by -2.