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

Toán Lớp 6: x(x+y)=2 thanks ===============================================================

Toán Lớp 6: x(x+y)=2
thanks
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Comments ( 2 )

  1. Giải đáp:
     x.(x+y)=2 (x,y \in Z)
    Nếu x=1 ; x+y = 2 ; 2 – x =y;=>y= 2-1 = 1  
    Nếu x=-1 ; x+ y = -2 ; 2-x=y; =>y= -2-(-1) = -1
    Nếu x=-2 ; x+y = -1 ; 2-x =y;=>y= -1-(-2)=1
    Nếu x=2;x+y = 1 ; 2-x =y ; => y = 1-2 = -1
    Vậy (x;y)=(1;1);(-1;-1);(-2;1);(2;-1)

  2. x . ( x + y ) = 2 = 1 . 2 = ( – 1 ) . ( – 2 )
    Nếu x = 1 ⇒ x + y = 2 ⇒ y = 2 – 1 = 1
    Nếu x = – 1 ⇒ x + y = – 2 ⇒ y = – 2 – ( – 1 ) = – 1 
    Nếu x = 2 ⇒ x + y = 1 ⇒ y = 1 – 2 = – 1
    Nếu x = – 2 ⇒ x + y = – 1 ⇒ y = – 1 – ( – 2 ) = 1
    Vậy , { x ; y } ∈ { ( 1 ; 1 ) ; ( – 1 ; – 1 ) ; ( 2 ; – 1 ) ; ( – 2 ; 1 ) } .

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