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

Toán Lớp 8: (2x-1)^2-25=0 b)8x^3-50x=0

Home/ Toán Lớp 8: (2x-1)^2-25=0 b)8x^3-50x=0

Toán Lớp 8: (2x-1)^2-25=0 b)8x^3-50x=0

Tháng Hai 4, 2023 Toán học 2 Comments 0 views

Toán Lớp 8: (2x-1)^2-25=0 b)8x^3-50x=0

Comments ( 2 )

  1. thanhbinh2k5
    thanhbinh2k5
    4 Tháng Hai, 2023 at 2:28 sáng
    Reply
    @Kem
    a, (2x – 1)² – 25 = 0
    (2x – 1)²= 0 + 25 = 25
    ⇒ TH1:2x-1 = 5 ⇔ 2x = 6 ⇔ x = 3
    ⇒TH2: 2x – 1 = -5 ⇔ 2x = -4 ⇔ x = -2
    b, 8x³-50x=0
    ⇔ x(8x²-50) = 0
    ⇒ TH1: x = 0
    ⇒TH2: x² = 25/4 ⇔ x ± 5/2

  2. catlantuong
    catlantuong
    4 Tháng Hai, 2023 at 2:28 sáng
    Reply
    Giải đáp:
    (2x-1)^2-25=0
    <=>(2x-1-5)(2x-1+5)=0
    <=>(2x-6)(2x+4)=0
    <=>(x-3)(x+2)=0
    <=> \(\left[ \begin{array}{l}x-3=0\\x+2=0\end{array} \right.\) 
    <=> \(\left[ \begin{array}{l}x=3\\x=-2\end{array} \right.\) 
    b)8x^3-50x=0
    <=>2x(4x^2-25)=0
    <=>2x(2x-5)(2x+5)=0
    <=> \(\left[ \begin{array}{l}2x=0\\2x-5=0\\2x+5=0\end{array} \right.\) 
    <=> \(\left[ \begin{array}{l}x=0\\2x=5\\2x=-5\end{array} \right.\) 
    <=> \(\left[ \begin{array}{l}x=0\\x=\dfrac52\\x=-\dfrac52\end{array} \right.\) 

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

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