AlgebraMediumA number from two equal expressions with distribution
Algebra practice question
Twice the sum of a number and four is equal to seven less than three times the number. What is the number?
Answer: 15
2(n + 4) = 3n − 7, so 2n + 8 = 3n − 7 and n = 15.
Common wrong answers
- If you answered 1
- 1 comes from 2n + 8 = 3n + 7 (wrong sign on the 7).
- If you answered 11
- 11 comes from 2n + 4 = 3n − 7, forgetting to distribute the 2 to the 4.
- If you answered -15
- −15 comes from moving the terms with the wrong signs.
More Algebra questions
- Medium
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If y = 2x − 1 and 3x + y = 14, what is the value of x? - Medium
If |2x − 3| = 7, what is the sum of all possible values of x? - Medium
Line k has equation y = (2/3)x + 1. Which equation represents a line perpendicular to line k?
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