Use the annihilator method to determine the form of a particular solution for the given equation. z triple prime minus 6 z double prime plus 9 z prime equals x squared minus e Superscript 3 x Find a differential operator that will annihilate the nonhomogeneity e Superscript 3 x Baseline minus x squared. Upper D squared (Upper D minus 3 )(Type the lowest-order annihilator that contains the minimum number of terms. Type your answer in factored or expanded form.) What is the form of the particular solution?