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