Which of the following expressions cannot be written as an integer? Square 49
-3^0
1.2x10^-2
18/3

1.2x10^-2 cannot be written as an integer.

Allow me to write the other three choices as integers.

Square 49 or square root of 49( I am not sure which you meant but both can be written as an integer)

Square root of 49 = 7
49 squared = 2401

-3^0 = 1

18/3 = 6

All these solutions are integers except the remaining solution.