I'm working on undetermined coefficients for nonhomogeneous equations. I have an equation that is equal to 3xe^x. For an earlier one that was equal to e raised to 8x, I used Ae^8x; but on this one, obviously that won't work. I don't know what I should be looking at. I tried Axe^x but no dice on that one either. I know things are supposed to cancel but for two terms multiplied together, how does that work for cancelling purposes? Is it really just a guessing game as to what the form of the particular solution should be?