已知x+y=3又1/2,xy=-3/2,求4x+3xy+4y的值

问题描述:

已知x+y=3又1/2,xy=-3/2,求4x+3xy+4y的值

 4x+3xy+4y
   =4(x+y)+3xy
   =4×(3又1/2)+3×(-3/2)
  =19/2

4x+3xy+4y
=(4x+4y)+3xy
=4(x+y)+3xy
=4×(3又1/2)+3×(-3/2)
=19/2