运用乘法公式计算 ❶﹙-4x-3y﹚² ❷﹙x+2y-3﹚﹙x-2y+3﹚

运用乘法公式计算 ❶﹙-4x-3y﹚² ❷﹙x+2y-3﹚﹙x-2y+3﹚
运用乘法公式计算 ❶﹙-4x-3y﹚² ❷﹙x+2y-3﹚﹙x-2y+3﹚

运用乘法公式计算 ❶﹙-4x-3y﹚² ❷﹙x+2y-3﹚﹙x-2y+3﹚

1、=（4x+3y）^2=16x^2  +24xy +9y^2

2、=[x+(2y+3)][x-(2y+3)]=x^2-(2y+3)^2=x^2-4y^2-12y-9

(-4x - 3y)"
= [-(4x + 3y)]"
= (4x + 3y)"
= (4x)" + 2(4x)(3y) + (3y)"
= 16x" + 24xy + 9y"

(x + 2y - 3)(x - 2y + 3)
= [ x + (2y - 3)][ x - (2y - 3)]
= x" - (2y - 3)"

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(-4x - 3y)"
= [-(4x + 3y)]"
= (4x + 3y)"
= (4x)" + 2(4x)(3y) + (3y)"
= 16x" + 24xy + 9y"

(x + 2y - 3)(x - 2y + 3)
= [ x + (2y - 3)][ x - (2y - 3)]
= x" - (2y - 3)"
= x" - [ (2y)" - 2(2y)3 + 3" ]
= x" - [ 4y" - 12y + 9 ]
= x" - 4y" + 12y - 9

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