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Question

$(\sqrt{5} + \sqrt{11})(\sqrt{5} - \sqrt{11})$ is equal to:

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
-6

Simplify Radical Expression $(\sqrt{5} + \sqrt{11})(\sqrt{5} - \sqrt{11})$

The given expression is in the form of a difference of squares, which follows the algebraic identity: $(a+b)(a-b) = a^2 - b^2$

In this expression, let $a = \sqrt{5}$ and $b = \sqrt{11}$.

Applying the difference of squares formula:

$(\sqrt{5} + \sqrt{11})(\sqrt{5} - \sqrt{11}) = (\sqrt{5})^2 - (\sqrt{11})^2$

Now, we evaluate the squares:

  • $(\sqrt{5})^2 = 5$
  • $(\sqrt{11})^2 = 11$

Substitute these values back into the equation:

$5 - 11$

Performing the subtraction:

$-6$

Thus, the expression $(\sqrt{5} + \sqrt{11})(\sqrt{5} - \sqrt{11})$ simplifies to $-6$.

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