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Question
Assertion: 98 × 102 = 9996
Reason: (a + b)(a – b) = a2 – b2
Options
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
Assertion (A) is true but Reason (R) is false.
Assertion (A) is false but Reason (R) is true.
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Solution
Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Explanation:
Assertion: 98 × 102 = 9996 is true.
This can be evaluated using the algebraic identity:
(a + b)(a – b) = a2 – b2
Here, 98 × 102 can be seen as (100 – 2)(100 + 2).
Applying the identity:
(100 – 2)(100 + 2)
= 1002 – 22
= 10000 – 4
= 9996
Reason states the identity used, which is true and crucial for the explanation of the assertion.
Thus, both Assertion and Reason are true and Reason correctly explains the Assertion.
