Answer:
Below
Step-by-step explanation:
Difference= ‘-’
=

x+6 is x+6. It's an expression. Not sure what you need help with.
((x^2-3x-18)/(x+3))
((x-6)(x+3))/(x+3)
The x+3 on top cancels out the x+3 on the bottom so all you have left is
x-6
Hope I didn't mess up for your sake!