Hi.
You can do this!! Start with the answer, which the problem gives you: It's -8. Then go from there to make an equation. The problem says you get to -8 by adding 9 to some number and then taking whatever sum that is and multiply it by -2.
So it would look like this:
-8 = (some number + 9) (-2)
Now, let's use "x" for that unknown number.
-2(x + 9) = -8
From here, you could solve for x:
-2x - 18 = -8
-2x = 10
x = -5
Let's see if that's correct:
-2 (x + 9) = -8
-2 (-5 + 9) = -8
10 - 18 = -8
Yes, that's right!!
