问题 计算题

计算:

(1)(x+3)2(x-3)2

(2)(x+2y-z)2

(3)(2x-y)(2x+y)-(2x-y)2

答案

解:(1)原式=[(x+3)(x-3)]2=(x2-9)2=x4-18x2+81;

(2)原式=[(x+2y)-z]2=(x+2y)2-2x(x+2y)+ z2=x2+4y2+x2+4xy-2xz-4yz;

(3)原式=(2x-y)[2x+y-(2x-y)]=(2x-y)(2x+y-2x+y)=(2x-y)·2y=4xy-2y2

选择题
单项选择题 A2型题