xy互为相反数,ab互为倒数,求1/2(x+y)+3ab=?

xy互为相反数,ab互为倒数,求1/2(x+y)+3ab=?
xy互为相反数,ab互为倒数,求1/2(x+y)+3ab=?

xy互为相反数,ab互为倒数,求1/2(x+y)+3ab=?
x+y=0
ab=1
所以1/2(x+y)+3ab=3

xy互为相反数，则和为0
ab互为倒数，则积为1
所以，1/2(x+y)+3ab=0.5*0+3*1=3