计算: (1)(2m-3n)2; (2)(x+2y-z)2.

问题描述:

计算:
(1)(2m-3n)2
(2)(x+2y-z)2

(1)原式=4m2-12mn+9n2
(2)原式=(x-z)2+4y(x-z)+4y2=x2-2xz+z2+4xy-4yz+4y2