The answer to this problem is not a real number. In order to get a square root of a negative number we use the letter (i). (i) is not a variable. It is similar to pi it has a value. The value of i = √-1.

    √-25            First of all you have to figure out what the factors of 25 are. We know them to be 1, 5 &25

    √25 = 5       We are left with 5√-1

    We simplify 5√-1 as:           5i