SAT Math Multiple Choice Question 459: Answer and Explanation

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Test Information

Question: 459

9.

Which of the following is the y-coordinate of the solution to the system of equations given above?

  • A. –8
  • B. –2
  • C. 2
  • D. 4

Correct Answer: B

Explanation:

B

Difficulty: Medium

Category: Heart of Algebra / Systems of Linear Equations

Strategic Advice: This system is set up perfectly to solve using substitution because both equations are already solved for y.

Getting to the Answer: Set both x expressions equal to one another and solve. Multiply the whole equation by 4 first, to get rid of the fractions.

The question asks for the y-coordinate of the solution, so substitute 4 for x in either equation and solve for y.

As an alternate method, because the equations are already in slope-intercept form, you could graph both equations in your calculator and find the point of intersection, which is (4, –2).

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