Step-by-step explanation: To simplify the square root of -40, think of the square root of -40 as the square root of -1 × the square root of 40.
The square root of -1 can be represented by the imaginary number <em>i</em>. So we have <em>i</em> × the square root of 40 or <em>i</em> .
Next, root 40 breaks down breaks down to 2 root 10. We can see this by setting up a factor tree for 40. 40 is 2 x 20, 20 is 2 x 10, and 10 is 2 x 5. We have a pair of 2's in our factor tree and we have 2 x 5 at the bottom.
So we have <em>i</em> x 2 root 10 or 2<em>i</em> .