SAT Math Multiple Choice Question 543: Answer and Explanation

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Test Information

Question: 543


Where will the line shown in the graph above intersect the x-axis?

  • A. –5.5
  • B. –5
  • C. –4.5
  • D. –4

Correct Answer: B



Difficulty: Easy

Category: Heart of Algebra / Linear Equations

Strategic Advice: Finding an x-intercept is easy when you know the equation of the line—it's the value of x when y is 0. Notice that the answer choices are very close together. This means you shouldn't just estimate visually. Take the time to do the math.

Getting to the Answer: Everything you need to write the equation is shown on the graph—just pay careful attention to how the grid-lines are labeled. The y-intercept is 10 and the line rises 2 units and runs 1 unit from one point to the next, so the slope is This means the equation of the line, in slope-intercept form, is y = 2x + 10. Now, set the equation equal to zero and solve for x:

The line will intersect the x-axis at –5.

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