SOLUTION: how do I do this problem? (squreroot 7 -2)(squareroot 7 -8)

Question 112906: how do I do this problem? (squreroot 7 -2)(squareroot 7 -8)
Answer by checkley71(8403) (Show Source): You can put this solution on YOUR website!
SQRT(7-2)*SQRT(7-8)
SQRT5*SQRT-1
MY MISTAKE:
SQRT(5*-1)
SQRT-5
OR
iSQRT5 (i=SQRT-1)