(a+2b-1)²与(2x+y+z)(2x-y-z)这两题请详解,

你是要这两个展开么?第一个(a+2b-1)²=[a+(2b-1)]²=a²+2a(2b-1)+(2b-1)²=a²+4ab-2a+4b²-4b+1 (2x+y+z)(2x-y-z)=[2x+(y+z)][2x-(y+z)]=4x²-2x(y+z)+2x(y+z)-(y+z)²=4x²-y²-2yz-z²