已知a.b是有理数,且满足Ia-1I+I2-bI=0,求a-b的值.
问题描述:
已知a.b是有理数,且满足Ia-1I+I2-bI=0,求a-b的值.
答
Ia-1I+I2-bI=0
绝对值大于等于0
也只有0+0=0
所以Ia-1I=0;I2-bI=0,
解得a=1 ,b=2
所以a-b=1-2=-1