Only do it if you know it dont guess

You just put -4 in X's place and thats the answer, you can't simplify it. 

If x = -4, you now just need to plug it in. (-4*-4)+5(-4)+7

So using the rules of pemdas, we multiply first. So -4 * -4 is 16. 

16 + 5(-4) + 7

Now we multiply again. 5 * -4 = -20

16 + (-20) + 7

Finally, we add. So 16 + -20 + 7 is 3

The answer is 3

Hope that helped! If you dont understand something just ask and i can re explain!

Polar coordinates is 8,9