Question 142860
For this one you've really got to be careful with your signs and squares.

Heres the key:
  -9 * -9 = 81....that little 2 next to the nine only means your times -9 by itself twice. Then you've got to remember that 2 negatives multipylied together equals a positive. 
  -2 * -2 = 4...same thing
You end up with 81/4, which sadly is a decimal (20.25)..I really do like it much better when its a whole #...
As a math student you should really get to know your square root numbers really well. 4,9,16,25,36,49,64,81,100,121,144....and so on.