{[(5x+2y)²-(5x-2y)²]+(x-3y)²-（x²-16y²)(x-4y)÷(x+4y)}÷7y={[(5x+2y+5x-2y)(5x+2y-5x+2y)]+(x-3y)²-(x-4y)(x+4y)(x-4y)÷(x+4y)}÷7y=[40xy+(x-3y)²-(x-4y)²]÷7y=[40x...