Solving Linear Equations: Distributive Property Answers

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Markus scored 85, 92, 82, and 94 on the first four tests of the semester. His teacher has not yet told him his score on his fifth test, but did tell him that his score on the fifth test is five points lower than the average (arithmetic mean) of all five tests. Which equation could Markus use to determine the score of the fifth test, x?

Use the drops-downs to justify how Heidi arrived at each step.