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

Toán Lớp 8: tim x a, 3x^2-5x+2=0 b,2x^2+3x-5=0 nhanhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Tháng Mười Một 28, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: tim x
a, 3x^2-5x+2=0
b,2x^2+3x-5=0
nhanhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Comments ( 2 )

  1. giahan44
    giahan44
    28 Tháng Mười Một, 2022 at 3:09 sáng
    Reply
    a)3x^2-5x+2=0
    -> 3x^2-3x-2x+2=0
    ->3x(x-1)-2(x-1)=0
    ->(x-1)(3x-2)=0
    ->\(\left[ \begin{array}{l}x-1=0\\3x-2=0\end{array} \right.\) 
    ->\(\left[ \begin{array}{l}x=1\\x=\frac{2}{3}\end{array}\right.\)
    b)2x^2+3x-5=0
    ->2x^2+5x-2x-5=0
    ->2x(x-1)+5(x-1)=0
    ->(x-1)(2x+5)=0
    ->\(\left[ \begin{array}{l}x-1=0\\2x+5=0\end{array} \right.\) 
    ->\(\left[ \begin{array}{l}x=1\\x=-\frac{5}{2}\end{array} \right.\)
     

  2. thanhbinh2k5
    thanhbinh2k5
    28 Tháng Mười Một, 2022 at 3:09 sáng
    Reply
    #Sad
    a)
    3x^2-5x+2 = 0
    ⇔ 3x^2-3x-2x+2 = 0
    ⇔ (3x^2-3x)-(2x-2) = 0
    ⇔ 3x(x-1)-2(x-1) = 0
    ⇔ (3x-2)(x-1) = 0
    ⇔ \(\left[ \begin{array}{l}3x-2=0\\x-1=0\end{array} \right.\) 
    ⇔ \(\left[ \begin{array}{l}3x=2\\x=1\end{array} \right.\) 
    ⇔ \(\left[ \begin{array}{l}x=\dfrac{2}{3}\\x=1\end{array} \right.\)
    \text{Vậy S=} {2/3; 1}
    b)
    2x^2+3x-5 = 0
    ⇔ 2x^2+5x-2x-5 = 0
    ⇔ (2x^2-2x)+(5x-5) = 0
    ⇔ 2x(x-1)+5(x-1) = 0
    ⇔ (2x+5)(x-1) = 0
    ⇔ \(\left[ \begin{array}{l}2x+5=0\\x-1=0\end{array} \right.\) 
    ⇔ \(\left[ \begin{array}{l}2x=-5\\x=1\end{array} \right.\) 
    ⇔ \(\left[ \begin{array}{l}x=-\dfrac{5}{2}\\x=1\end{array} \right.\) 
    \text{Vậy S=} {-(5)/(2); 1}
     

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

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