计算:(a+2)(3-a)+(2x+y+z)(2x-y-z)

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计算:(a+2)(3-a)+(2x+y+z)(2x-y-z)计算:(a+2)(3-a)+(2x+y+z)(2x-y-z)计算:(a+2)(3-a)+(2x+y+z)(2x-y-z)解(a+2)(3-a

计算:(a+2)(3-a)+(2x+y+z)(2x-y-z)
计算:(a+2)(3-a)+(2x+y+z)(2x-y-z)

计算:(a+2)(3-a)+(2x+y+z)(2x-y-z)


(a+2)(3-a)+(2x+y+z)(2x-y-z)
=(3a-a²+6-2a)+[2x+(y+z)][2x-(y+z)]
=-a²+a+6+(2x)²-(y+z)²
=-a²+a+6+4x²-y²-z²-2yz