解：(2x-3y)²(2x+3y)² = [(2x-3y)(2x+3y)]² =（4x²-9y²）² =16x^4-2×4x²×9y²+81y^4 =16x^4-72x²y²+81y^4希望你明白
原式=[(2x-3y)(2x+3y)]^2=(4x^2-9y^2)^2=16x^2-72x^2y^2+81y^4
16x＾4－81y＾4
