(x-2)(x+3)-(x-2)(x+4)

You can see there are two terms and they each have a common factor (x-2), so

if we take out the common factor it becomes

(x-2) [x+3 - (x+4)]

Now it's just a matter of removing the brackets around x+4 when there is

a negative sign in front of it.

(x-2) [x+3-x-4)]

And this can be simplified finally to .....

this is left as an exercise for you to finish. 

🐔   🐔   🐔