# How do you simplify # 2sqrt(-27) • sqrt(-3)#?

##### 1 Answer

Mar 2, 2018

#### Explanation:

It is interesting to note what you should not do.

Note that:

#sqrt(a) sqrt(b) = sqrt(ab)#

if at least one of

In our example we have

#color(red)(cancel(color(black)(2sqrt(-27)sqrt(-3) = 2sqrt((-27)(-3)) = 2sqrt(81) = 2*9 = 18)))#

Instead, note that if

So we have:

#2sqrt(-27)sqrt(-3) = 2i sqrt(27) i sqrt(3) = 2i^2 sqrt(27)sqrt(3) = -2sqrt(81) = -2*9 = -18#