Advanced MathEasy–MediumLength of a rectangle from area and width
Advanced Math practice question
A rectangle has an area of 6x³ − 9x² square units and a width of 3x² units, where x > 2. Which expression represents the length of the rectangle, in units?
- A. 2x − 3Correct
- B. 2x − 9
- C. 2x² − 3
- D. 2x − 3x
Answer: A. 2x − 3
Length = area ÷ width. Divide each term: 6x³/3x² = 2x and 9x²/3x² = 3, so 2x − 3.
Why the other answers are wrong
- B. 2x − 9
- 2x − 9 forgets to divide the 9 by 3.
- C. 2x² − 3
- 2x² − 3 subtracts the wrong exponent in the first term (x³/x² = x).
- D. 2x − 3x
- 2x − 3x keeps an x on the second term; x²/x² = 1.
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