3xy - 4xyz + 3x -8yx + 5yzx - 9x
First remember the order of the variables don't mean a thing due to the communitive laws.
3xy - 8xy -4xyz + 5xyz +3x - 9x
change the order of the variables to reflect the same way, rewrite teh eqaution with common terms next to each other
-5xy +xyz -6x