Multiply.

     `(4-sqrt(5))(3+sqrt(5))`

`(4-sqrt(5))(3+sqrt(5))=`  

Box 1: Enter your answer as a number (like 5, -3, 2.2172) or as a calculation (like 5/3, 2^3, 5+4)
Enter DNE for Does Not Exist, oo for Infinity