Which choice is equivalent to the expression below?

[tex]\(\sqrt{-121}\)[/tex]

A. [tex]\(-\sqrt{11}\)[/tex]
B. [tex]\(-\sqrt{11i}\)[/tex]
C. [tex]\(\sqrt{11i}\)[/tex]
D. [tex]\(11\)[/tex]
E. [tex]\(-11\)[/tex]



Answer :

To determine the equivalent expression for [tex]\(\sqrt{-121}\)[/tex], we need to find the square root of a negative number.

First, recall that the square root of a negative number involves the imaginary unit [tex]\(i\)[/tex], where [tex]\(i\)[/tex] is defined as [tex]\(\sqrt{-1}\)[/tex].

Given the expression:
[tex]\[ \sqrt{-121} \][/tex]

We can break this down using the property of square roots for negative numbers:
[tex]\[ \sqrt{-121} = \sqrt{121 \cdot (-1)} \][/tex]

Using the property of square roots that [tex]\(\sqrt{a \cdot b} = \sqrt{a} \cdot \sqrt{b}\)[/tex], we get:
[tex]\[ \sqrt{121 \cdot (-1)} = \sqrt{121} \cdot \sqrt{-1} \][/tex]

We know:
[tex]\[ \sqrt{121} = 11 \quad \text{and} \quad \sqrt{-1} = i \][/tex]

Therefore:
[tex]\[ \sqrt{-121} = 11 \cdot i = 11i \][/tex]

Now, we need to determine which of the choices matches this result. The expression [tex]\(11i\)[/tex] corresponds to the imaginary part of the number.

Reviewing the choices:
A. [tex]\(-\sqrt{11}\)[/tex] is a real number and does not involve [tex]\(i\)[/tex].
B. [tex]\(-\sqrt{11 i}\)[/tex] is not equivalent to our result since it involves a square root of an imaginary unit.
C. [tex]\(\sqrt{11 i}\)[/tex] is not equivalent to our result and improperly combines [tex]\(i\)[/tex] inside the square root.
D. [tex]\(11/\)[/tex] is not mathematically valid notation and incomplete.
E. [tex]\(-11\)[/tex] is a real number and does not involve [tex]\(i\)[/tex].

None of the choices directly correspond to [tex]\(11i\)[/tex].

Thus, the best choice equivalent to [tex]\(11i\)[/tex] from the given options would technically be none, as none match exactly. However, we established that the correct simplified and mathematical equivalent of [tex]\(\sqrt{-121}\)[/tex] is:
[tex]\[ 11i \][/tex]

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