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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 7: x-y=6-2xy Tìm các số nguyên x,y

Toán Lớp 7: x-y=6-2xy Tìm các số nguyên x,y

Comments ( 1 )

  1. Lời giải chi tiết:
    x-y=6-2xy
    =>6-2xy-(x-y)=0
    =>2xy-x+y=6-0
    =>x.(2y-1)+y=6
    =>2x.(2y-1)+2y=12
    =>2x.(2y-1)+(2y-1)=12-1
    =>(2y-1).(2x+1)=11
    TH1: {(2y-1=11),(2x+1=1):} =>{(2y=12),(2x=0):} =>{(y=6),(x=0):}
    TH2: {(2y-1=-11),(2x+1=-1):} =>{(2y=-10),(2x=-2):} =>{(y=-5),(x=-1):}
    TH3: {(2y-1=1),(2x+1=11):} =>{(2y=2),(2x=10):} =>{(y=1),(x=5):}
    TH4: {(2y-1=-1),(2x+1=-11):} =>{(2y=-2),(2x=-12):} =>{(y=-1),(x=-6):}
    Vậy (x,y)∈{(0,6);(-1,-5);(5,1);(-6,-1)}
    @hoangca159357

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222-9+11+12:2*14+14 = ? ( )