Toán Lớp 7: lx-2020l+ly-2021l=0 giai giup em
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Toán Lớp 7: lx-2020l+ly-2021l=0 giai giup em
Comments ( 2 )
Ta có:
{(|x-2020|ge0forallx),(|y-2021|ge0forally):}
=>|x-2020|+|y-2021|ge0
Mà |x-2020|+|y-2021|=0
=>{(|x-2020|=0),(|y-2021|=0):}
=>{(x-2020=0),(y-2021=0):}
=>{(x=0+2020),(y=0+2021):}
=>{(x=2020),(y=2021):}
Vậy x=2020;y=2021