The circle and the line intersect at two points. What is the sum of the -coordinates of these points?

Answer and explanation

Correct answer: A.

  1. Step 1: Substitute: , so and .
  2. Step 2: This factorises as , so or .
  3. Step 3: Then or . The sum of the -values is .
Answer
.
Why not the others: is the sum of the -coordinates, ; is , the sum of the absolute values of the -coordinates; and do not match .

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