The answer you are looking for is -11/10 or - 1 1/10.
To find this answer you must first make the denominators the same. To do this, multiply 2/5 by 2/2 to get 4/10. Finally, subtract the two fractions, keeping in mind the denominators stay the same. -7/10 - 4/10 = -11/10 or - 1 1/10.
