数学题计算(2x+Y-z+5)(2x-y+z+5)等于

问题描述:

数学题计算(2x+Y-z+5)(2x-y+z+5)等于
还有(a+3b+2c)(a-3b+6c)等于多少

(2x+Y-z+5)(2x-y+z+5)=[(2x+5)+(y-z)][(2x+5)-(y-z)]=(2x+5)²-(y-z)²=4x²+20x+25-(y²-2yz+z²)=4x²+20x+25-y²+2yz-z²(a+3b+2c)(a-3b+6c)=a(a-3b+6c)+3b(a-3b+6c)+2...