x and y are real numbers satisfying the conditions 2 < x < 3 and –8 < y < –7. Which of the following expressions will have the least value?
Explanation:
Option 2 can easily be eliminated as it will give positive value, while both option 1 and 3 will be negative.
∵ x2 will fall in the range 4 < x2 < 9.
∵ 5x will fall between 10 < 5x < 15.
∴ 5x > x2 Also, 5x < 6x < 7x < ... and –8 < y < –7 ∴ 5xy > 6xy > 7xy > ...
Hence, option (d).
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