已知M=3x2-2xy+y2,N=2x2+xy+3y2.求(1)M+N;(2)M-N

已知M=3x2-2xy+y2,N=2x2+xy+3y2.求(1)M+N;(2)M-N.
2025-05-15 03:24:02
推荐回答(1个)
回答1:

(1)∵M=3x2-2xy+y2,N=2x2+xy+3y2
∴M+N=3x2-2xy+y2+2x2+xy+3y2=5x2-xy+4y2
(2)∵M=3x2-2xy+y2,N=2x2+xy+3y2
∴M-N=3x2-2xy+y2-2x2-xy-3y2=x2-3xy-2y2