Question

((4x-3y)^2-(4x+3y)^2):(4xy)

Answer 1

$\boldsymbol{((4x-3y)^2-(4x+3y)^2):(4xy)=}\\\\=\dfrac{(4x-3y)^2-(4x+3y)^2}{4xy}=\\\\=\dfrac{(4x-3y+4x+3y)(4x-3y-4x-3y)}{4xy}=\\\\=\dfrac{8x\cdot (-6y)}{4xy}=-\dfrac{48xy}{4xy}\boldsymbol{=-12}$

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Использована формула разности квадратов

a² - b² = (a + b)(a - b)