Mathematics
Assertion (A) : Use appropriate identity, we get 22.5 x 21.5 = 484.75.
Reason (R) : The product: (x + y)(x - y) = x2 - y2.
Both A and R are correct, and R is the correct explanation for A.
Both A and R are correct, and R is not the correct explanation for A.
A is true, but R is false.
A is false, but R is true.
Identities
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Answer
Solving,
(x + y)(x - y) = x(x - y) + y(x - y)
= x2 - xy + xy - y2
= x2 - y2
So, reason (R) is true.
Solving,
⇒ 22.5 x 21.5
⇒ (22 + 0.5)(22 - 0.5)
Using the identity; (x + y)(x - y) = x2 - y2
= (22)2 - (0.5)2
= 484 - 0.25
= 483.75
So, assertion (A) is false.
Hence, option 4 is the correct option.
Answered By
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