Answer: x = -20
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Step-by-step explanation:
The expression 18+x is the same as x+18. This is because we can add two numbers in any order to get the same result. Example: 2+3 = 3+2 = 5.
Whats happening to the x is we add on 18. To isolate x, we undo this operation to subtract 18 from both sides.
Keep in mind that subtracting a negative from a negative will have us add the positive versions of the number, and the final result is ultimately negative. So that's why -2-18 = -20. You can think of it as 2+18 = 20 and you make the 20 negative.
Here's how the steps look like
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18 + x = -2
x + 18 = -2
x + 18 - 18 = -2 - 18 ... subtracting 18 from both sides
x + 0 = -20
x = -20