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

Toán Lớp 8: a) 2x (x – 5) – x (3 + 2x) = 26 b) 5x + $x^{2}$ = 0

Toán Lớp 8: a) 2x (x – 5) – x (3 + 2x) = 26
b) 5x + $x^{2}$ = 0

Comments ( 2 )

  1. a)2x.(x-5)-x(3+2x)=26
    x.[2.(x-5)-(3+2x)]=26
    x.(2x-10-3-2x)=26
    x.(-13)=26
    x=26:(-13)
    x=-2
    C2:
    ->2x.(x-5)-x(3+2x)-26=0
    2x^2 – 2.5 -(3x+2x^2)-26=0
    2x^2-10x-3x-2x^2-26=0
    (2x^2-2x^2)-(10x+3x)-26=0
    -13x-26=0
    -13x=0+26=26
    x=26:(-13)=-2
    b)5x + x^2 =0
    x.(5+x)=0
    TH1:x=0
    TH2:5+x=0->x=0-5=-5
    => x∈{0;-5}
     

  2. Giải đáp+Lời giải và giải thích chi tiết:
     a) 2x(x-5)-x(3+2x)=26
    ⇒ 2x²-10x-3x-2x²=26
    ⇒-13x=26
    ⇒x=-26/13
    ⇒x=-2
    Vậy x=-2
    b) 5x+x^2=0
    ⇒x(5+x)=0
    ⇒\(\left[ \begin{array}{l}x=0\\5+x=0\end{array} \right.\) 
    ⇒\(\left[ \begin{array}{l}x=0\\x=-5\end{array} \right.\) 
    Vậy x∈{0,-5}

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