Question

Simplify. 3√-28

A 2i√7
B 12i√7
C 61√7
D -6i√7

Answer 1

C

Explanation:

We want to simplify the expression:

`\displaystyle 3 √(-28)`

Rewrite:

`\displaystyle = 3 √( 4\cdot 7 \cdot -1)`

Rewrite:

`\displaystyle = 3 \cdot √(4) \cdot √(7) \cdot √(-1)`

Simplify. Let i = √(-1). Hence:

`\displaystyle = 3 \cdot \left(2\right) \cdot \left(i\right) \cdot √(7)`

Multiply:

`\displaystyle = 6i√(7)`

In conclusion, our answer is C.