Advanced MathEasy–MediumArea of a rectangle as a product of binomials
Advanced Math practice question
A rectangle has length x + 4 metres and width x + 2 metres. Which expression represents its area, in square metres?
- A. x² + 6x + 8Correct
- B. x² + 8
- C. 2x + 6
- D. x² + 6x + 6
Answer: A. x² + 6x + 8
Area = (x + 4)(x + 2) = x² + 2x + 4x + 8 = x² + 6x + 8.
Why the other answers are wrong
- B. x² + 8
- x² + 8 forgets the two cross terms (2x and 4x).
- C. 2x + 6
- 2x + 6 is half the PERIMETER, not the area.
- D. x² + 6x + 6
- x² + 6x + 6 adds 4 and 2 for the constant; it should be their product, 8.
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