16Hit1600
AlgebraVery hardLinear function from its two intercepts

Algebra practice question

The graph of the linear function g in the xy-plane has x-intercept 6 and y-intercept −4. Which of the following defines g?

  1. A. g(x) = (2/3)x − 4Correct
  2. B. g(x) = (3/2)x − 4
  3. C. g(x) = −(2/3)x + 6
  4. D. g(x) = (2/3)x + 6

Answer: A. g(x) = (2/3)x − 4

The line rises 4 over a run of 6, so the slope is 2/3, and the y-intercept is −4.

Why the other answers are wrong

B. g(x) = (3/2)x − 4
The slope 3/2 is the reciprocal of the correct slope.
C. g(x) = −(2/3)x + 6
The intercepts are confused and the slope's sign is wrong.
D. g(x) = (2/3)x + 6
6 is the x-intercept, not the y-intercept.

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