f(x - n) - shift the graph n units right
f(x + n) - shift the graph n units left
f(x) - n - shift the graph n units down
f(x) + n - shift the graph n units up
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y = 2(x - 15)² + 3
y = 2(x -11)² + 3 = 2(x - 15 + 4)² + 3
Answer: shift the graph of y = 2(x - 15)² + 3 four units left.