Answer:
-74.
Explanation:
First, notice that we can divide it into 2 equations (1 on each side of the equal symbol).
1st step:
Replace where's x by -2 in the left equation:

2nd step:
Now, we will replace the squares with 16 in the second equation. Look:

So, the answer is -74.
We also can solve it in another way:

Now let's call the gray square as y in the second equation:

So, your final answer is -74.
Hope it helps! :D