计算题:(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2

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计算题:(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2
计算题:(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2

计算题:(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2
(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2
=4x^2+12xy+9y^2-16x^2+81y^2+4x^2-12xy+9y^2
=-8x^2+99y^2

(2x+3y)^2-(4x-9y)(4x+9y)+(2x-3y)^2
=4x^2+12xy+9y^2-16x^2+81y^2+4x^2-12xy+9y^2
=-8x^2+99y^2

-8x^2+90y^2