Algebra practice question

Answer: 4

Every point on the x-axis has y = 0. Substitute: 5x − 2(0) = 20, so 5x = 20 and x = 4. The x-intercept is (4, 0).

Common wrong answers

If you answered 20

20 is 5x, one step short. Divide by 5 to get x = 4.

If you answered −10

−10 is the y-intercept, from setting x = 0: −2y = 20. The x-intercept is where y = 0 instead.

If you answered −4

The sign is wrong: 5x = 20 gives x = +4. Setting y = 0 removes the −2y term entirely, so no negative is introduced.

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