Question

Difficulty: EasyTransformations in the Coordinate Plane

In the standard (x,y)(x,y) coordinate plane, the point A(−4,3)A(-4, 3) is reflected across the xx-axis and then translated 55 units to the right to map onto point A′A'. What are the coordinates of A′A'?

  1. (1,−3)(1, -3)Answer
  2. B
    (−9,−3)(-9, -3)
  3. C
    (1,3)(1, 3)
  4. D
    (9,3)(9, 3)
  5. E
    (−9,3)(-9, 3)

Answer

(1,−3)(1, -3)
Reflecting the point A(−4,3)A(-4, 3) across the xx-axis negates its yy-coordinate, resulting in (−4,−3)(-4, -3). Then, translating this point 55 units to the right increases its xx-coordinate by 55, which yields (−4+5,−3)=(1,−3)(-4 + 5, -3) = (1, -3).

Step-by-Step Solution

1
Reflect the point A(−4,3)A(-4, 3) across the xx-axis.
The rule for reflection across the xx-axis is (x,y)→(x,−y)(x, y) \rightarrow (x, -y). Applying this rule to A(−4,3)A(-4, 3) yields the intermediate point (−4,−3)(-4, -3).
A reflection across the xx-axis negates the yy-coordinate of the point while keeping the xx-coordinate the same.
2
Translate the reflected point (−4,−3)(-4, -3) by 55 units to the right.
The rule for translating a point hh units to the right is (x,y)→(x+h,y)(x, y) \rightarrow (x + h, y). Adding 55 to the xx-coordinate yields (−4+5,−3)=(1,−3)(-4 + 5, -3) = (1, -3).
Translating a point to the right increases its xx-coordinate by the translation distance.

Key Concept

Applying a sequence of coordinate transformations (reflection followed by translation) to a point.
Estimated Time:45s
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