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

Toán Lớp 6: 1. ( -134 ) + 51 . 134 + 48 . ( -134 ) 2. ( x + 2^4 ) . 7 ³ = 2. 7^4 3. 4 ² . ( 3x -11 ) ² = 256

Tháng Tư 19, 2022 Toán học 2 Comments 0 views

Toán Lớp 6: 1. ( -134 ) + 51 . 134 + 48 . ( -134 )
2. ( x + 2^4 ) . 7 ³ = 2. 7^4
3. 4 ² . ( 3x -11 ) ² = 256

Comments ( 2 )

  1. thanoanghha
    thanoanghha
    19 Tháng Tư, 2022 at 2:57 sáng
    Reply
    1. ( -134 ) + 51 . 134 + 48 . ( -134 )
    = – 134 . ( 1 – 51 + 48 )
    = – 134 . ( – 2 )
    = 268
    2. ( x + 2^4 ) . 7^3 = 2 . 7^4
    x + 2^4 = 2 . 7^4 : 7^3
    x = 2 . 7 – 2^4
    x = 14 – 16
    x = – 2
    $\text{Vậy x = – 2}$
    3 . 4^2 . ( 3x – 11 )^2 = 256
    3. 4^2 . ( 3x – 11 )^2 = 256
    ( 3x – 11 )^2 = 256 : 16
    ( 3x – 11 )^2 = 4^2
    ⇒ 3x – 11 = 4 hoặc 3x – 11 = – 4
    ⇒ 3 . x = 4 + 11 hoặc 3 . x = – 4 + 11
    ⇒ x = 15 : 3 hoặc x = 7 : 3
    ⇒ x = 5 hoặc x = 7/3
    Vậy x ∈ { 5; 7/3 }

  2. haiyemy
    haiyemy
    19 Tháng Tư, 2022 at 2:56 sáng
    Reply
    Lời giải chi tiết:
    1) (-134)+51.134+48.(-134)
    =(-134)+(-51).(-134)+48.(-134)
    =(-134).[1+(-51)+48]
    =(-134).(-2)
    =268
    2) (x+2^4).7^3=2.7^4
    =>x+16=2.7^4:7^3
    =>x+16=2.7
    =>x+16=14
    =>x=14-16
    =>x=-2
    Vậy x=-2
    3) 4^2.(3x-11)^2=256
    =>(3x-11)^2=256:16
    =>(3x-11)^2=16
    =>\(\left[ \begin{array}{l}3x-11=4\\3x-11=-4\end{array} \right.\)
    =>\(\left[ \begin{array}{l}3x=15\\3x=7\end{array} \right.\)
    =>\(\left[ \begin{array}{l}x=5\\x=\dfrac{7}{3}\end{array} \right.\)
    Vậy x∈{5;7/3}

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

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