If X lies between -3 and -1 and Y lies between -1 and 1, then X2 – Y2 lies between which two values?
If X lies between -3 and -1 and Y lies between -1 and 1, then X2 – Y2 lies between which two values? Correct Answer 1 and 8
Given:
X lies between -3 and -1 and Y lies between -1 and 1.
Concepts used:
a2 – b2 = (a – b) × (a + b)
Calculation:
-3 ≤ X ≤ -1
⇒ 1 ≤ X2 ≤ 9
-1 ≤ Y ≤ 1
⇒ 0 ≤ Y2 ≤ 1
⇒ 1 – 0 ≤ X2 – Y2 ≤ 9 – 1
⇒ 1 ≤ X2 – Y2 ≤ 8
∴ Expression X2 – Y2 lies between 1 and 8.
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Feb 20, 2025