The decimal number not equivalent to 5.7 is

1. 5.70

2. 5.07

3. 5.700

4. 5.7000

The value of a decimal number remains the same if extra zeros are written at the end. So, 5.7 = 5.70 = 5.700 = 5.7000. But 5.07 is different from 5.7.

Hence, option 2 is the correct option.