Question 740011
Both forms are correct.
.
Starting with your form:
x=(10/e^3 -10)/2
dividing each term by 2:
x= 5/e^3 - 5
common denominator is e^3:
x= 5/e^3 - 5(e^3/e^3)
x= 5/e^3 - (5e^3)/e^3
x= (5 - 5e^3)/e^3  (which is your teacher's format)