So our two equations are y=-8x-4 and y=-16, and since in both equations, something equals the same y, those two are the same. So we can combine the two into -16=-8x-4. In the question, they are asking to solve for x. So to do that, you need to isolate your variable. Now for solving algebraic equations, you use reverse PEMDAS (SADMEP), meaning you add 4 to both sides to clear the -4 one the rights side to get -12=-8x. Then you divide both sides by -8 to get 12/8, which simplifies to 3/2.
Step-by-step explanation:
36
squaring on both side
36 root is 6
6*6=36
[√6]2
cut root and square
answer 6
Using substitution:
first you have to express one variable in terms of the other, in this we can express y in terms of x:

Since both expressions are equal to y, you have to equal both expressions like this:

Now you can solve the equation:

Knowing x=10, you can use any of the expressions we found before to find y. In this case I'm going to use y= -x+9 because it's simpler but boy should give you the same result

So, the answer is x=10 and y=-1