已知A=5x^2y-3xy^2+4xy,B=7xy^2-2xy+x^2y,若A+B+2C=0,求C-A
问题描述:
已知A=5x^2y-3xy^2+4xy,B=7xy^2-2xy+x^2y,若A+B+2C=0,求C-A
答
解C=(-A-B)/2
=-2x^2y+xy-2xy^2
C-A=-7x^2y-3xy+xy^2