实数ab互为相反数,c、d互为倒数,x的绝对值为根号5
a+b=0 cd=1 X^2=5
x=正负根号5
x²+(a+b-cd)x+(√a+b+³√cd)
=5-x+1
=6-x
值为6+根号5和6-根号5