Question 4 • Algebra II
A graph has symmetry about the y-axis when the part to the left of the axis is a mirror image of the part to the right. In D, the crests at (−3, 1) and (3, 1) are equally far from the y-axis and have the same height, and the trough is on the y-axis at (0, −1). So the graph showing line symmetry about the y-axis is the one with crests at (−3, 1) and (3, 1).
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