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Explanation:
We get this point by doing two things.
If we started with x = -3, then x-2 = -3-2 = -5. Also, if we had y = -1 then y-7 = -1-7 = -8
So that's how we end up with Z(-3,-1) moving to Z ' (-5, -8)
You could also show your work like this
[tex](x,y) \to (x-2, y-7)\\\\(-3,-1) \to (-3-2, -1-7)\\\\(-3,-1) \to (-5, -8)\\\\[/tex]