Write $- 3 \sqrt { - 45 }$ in terms of i and simplify.
A) $- 9 i \sqrt { 5 }$
B) $9 i \sqrt { 5 }$
C) $- 9 \sqrt { 5 }$

Question

Quizplus · Accepted Answer

We know that the square root of a negative number is an imaginary number i times the square root of the positive version of the number. So, we have:

$- 3 \sqrt { - 45 } = -3i\sqrt{45} = -3i\sqrt{9 \cdot 5} = -3i \cdot 3 \sqrt {5 } = -9i\sqrt{5}$

Therefore, the correct choice is A.

Write −3−45- 3 \sqrt { - 45 }−3−45​ In Terms of I and Simplify