Question

已知三个互不相等得有理数既可以表示为1 a+b a的形式。还可表示为0 a分之b b的形式，求ab的值 帮忙坐下 急

Answer 1

A= {1, a+b, a }
B= {0, b/a, b}

∵ 0 is not equal to 1
case 1
if 1= b/a => a= b (a is not equal to 0) ---(1)
and case 1.1 if a= 0 contradict (1) (rejected )
and case 1.2 if a=b/a => a^2 = b
then from(1) a^2-a = 0 => a= 0 (rejected)
a = 1 => b =1
case 2
if 1= b
and case 2.1 if a=0 and b/a does not exist (rejected)
and case 2.2 if a= b/a => a^2 = b --(2)
and a+b = 0
from (2) a^2 - a = 0
==> a=1 or 0(rejected)
when a=1 =>b =1

from case 1 and case 2, we get
a=1 b=1 #

Answer 2

由题意，a+b，a中必有一个为0，又在b/a中a≠0，
∴a+b=0，那么b/a= -1，必有a= -1，
∴b=1，ab= -1

Answer 3

由题意，a+b，a中必有一个为0，又在b/a中a≠0，
∴a+b=0，那么b/a= -1，必有a= -1，
∴b=1，ab= -1