试卷导航
1.(1)原式=(a+b)²(a+b)
=(a²+2ab+b²)(a+b)
=a³+3a²b+3ab²+b³
(2)原式=(x-1)²(x-1)
=(x²-2x+1)(x-1)
=x³-x²-2x²+2x+x-1=x³-3x²+3x-1
(3)原式=[(a-b)-c]²
=(a-b)²-2(a-b)c+c²
=a²+b²+c²-2ab-2ac+2bc
2.(1)原式=(2a+b)²-1
=4a²+4ab+b²-1
(2)原式=[3x+(y+z)][3x-(y+z)]
=(3x)²-(y+z)²
=9x²-(y²+2yz+z²)
=9x²-y²-2yz-z²
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