已知xy+yy=3,xx+xy=-1/2,求2xx+3xy+yy的值
问题描述:
已知xy+yy=3,xx+xy=-1/2,求2xx+3xy+yy的值
答
2xx+3xy+yy
=2xx+2xy+xy+yy
=2(xx+xy)+xy+yy
=2*(-1/2)+3
=3-1
=2