原式=[6(2x-y)³-4y(y-2x)²]/[2(y-2x)²]=[6(2x-y)³-4y(2x-y)²]/[2(2x-y)²]=[6(2x-y)³÷[2(2x-y)²]-[4y(2x-y)²]÷[2(2x-y)²]=6÷2×(2x-y)³÷(2x-y)²-4...