15 or -23
I think you probably already turned this in but in case you haven't:
ST = 19 means that line segment ST is 19 units long. If we know that S is at -4, then T has to be 19 units away from -4, right?
So there's two directions we could go.
Add 19 to -4 to get 15, so T could be at 15. (If there's a line drawn between -4 and 15, it would be 19 units long.)
But the line could go left, towards negative infinity, too. So if we subtract 19 from -4, we'd get -23. T could also be at -23. (If there's a line drawn between -4 and -23, it would also be 19 units long. There's no such thing as a negative length.)
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