AlgebraHardEquation with parentheses on both sides
Algebra practice question
What value of x satisfies 5(x − 2) = 2(x + 4) + 3?
Answer: 7
Expand both sides: 5x − 10 = 2x + 8 + 3, so 5x − 10 = 2x + 11. Subtract 2x: 3x − 10 = 11. Add 10: 3x = 21, x = 7. Check: 5(5) = 25 and 2(11) + 3 = 25.
Common wrong answers
- If you answered 3
- 3 would come from 5x − 2 = 2x + 11 — the 5 wasn't distributed to the −2. Distribute: 5(x − 2) = 5x − 10.
- If you answered 6
- 6 comes from dropping the +3: 5x − 10 = 2x + 8 gives x = 6. The 3 outside the bracket is part of the right side.
- If you answered 21
- 21 is 3x, one step from the answer. Divide by 3.
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