[﹙y-3x﹚﹙-3x-y﹚-9﹙x-2y﹚²]÷3y
=[9x²-y²-9﹙x²-4xy+4y²)]÷3y
=(9x²-y²-9x²+36xy-36y²)÷3y
=(36xy-37y²)÷3y
=(36x-37y)÷3
=12x-37y/3
=12*（-2）-37*3/3
=-24-37
=-61