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A student reasons that (4,1) is a solution of y = 3x + 1 because x=1 when y=4. Explain and correct the student's error.

User Prexx
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1 Answer

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Final answer:

The student switched the x and y values, which is incorrect. By substituting x=4 into the equation y = 3x + 1, we find y equals 13, not 1. Hence, (4,1) is not a solution to the equation.

Step-by-step explanation:

The student made an error in reasoning that the point (4,1) is a solution to the equation y = 3x + 1 because they incorrectly switched the values of x and y. To find a solution to a linear equation, we substitute the x-value into the equation and solve for y, or vice versa. To verify whether (4,1) is a solution, we substitute x=4 into the equation and check if we get y=1.

To correct the student's error, let us do the substitution:

  • Substitute x=4 into the equation: y = 3(4) + 1.
  • Calculate the result: y = 12 + 1.
  • Confirm if this is y=1: y = 13 (this is not equal to 1).

Since after substituting, we get y=13 and not y=1, we conclude that the point (4,1) is not a solution to the equation y = 3x + 1.

User WBlasko
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