Replacing x with x-4 shifts the xy axis four units to the left. If we fix the blue V shape to not move while the xy axis does move, then it gives the illusion of the V shape moving 4 units to the right to end up producing the red curve.
You can use a table of values to compare the two functions or you could use a graphing tool to confirm the answer.
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Extra info:
Choice A will move the blue graph 4 units down
Choice B will move the blue graph 4 units up
Choice C will move the blue graph 4 units to the left
