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Math / Algebra / Grade 7 / ml7e1

The Unknown on Both Sides - Practice 1

Collect variable terms using matching operations, then check the original equation.

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Watch the lesson | Practice 2: new signs and coefficients

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Every x in one equation means the same number. Add or subtract the same expression on both sides, combine like terms, and divide by the remaining nonzero coefficient. Explain each step on paper.

Worked example

5x + 2 = 2x + 14. Subtract 2x: 3x + 2 = 14. Subtract 2: 3x = 12. Divide by 3: x = 4. Both original sides equal 22.

Worked example: 5x plus 2 equals 2x plus 14. Subtract 2x from both sides, subtract 2 from both sides, then divide both sides by 3 to find x equals 4. Both original sides equal 22.
A separate worked example. Apply each operation to both entire sides.
Question 1 Solve 4x + 3 = 2x + 15. What is x?
Question 2 Solve 7x - 5 = 3x + 7. What is x?
Question 3 Solve 2x + 11 = 5x + 20. What is x?
Question 4 Solve 6x - 8 = 2x - 8. What is x?
Question 5 Solve 9 - x = 2x - 6. What is x?