16Hit1600
AlgebraHardEquation of a line from a table

Algebra practice question

The table gives three points on a line: when x = 1, y = 7; when x = 2, y = 4; when x = 3, y = 1. Which equation represents the line?

  1. A. y = −3x + 10Correct
  2. B. y = 3x + 4
  3. C. y = −3x + 7
  4. D. y = 10x − 3

Answer: A. y = −3x + 10

y falls by 3 for each step of 1 in x, and at x = 1, −3 + 10 = 7.

Why the other answers are wrong

B. y = 3x + 4
This gives y = 7 at x = 1 but rises instead of falling.
C. y = −3x + 7
This gives y = 4 at x = 1.
D. y = 10x − 3
This gives y = 7 at x = 1 but then rises steeply.

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