1,tìm x 2.3 mũ x=162 2 mũ x – 15=17 (7 mũx -11)mũ 3 = 5 mũ 2+200 x mũ 10=x

Question

1,tìm x
2.3 mũ x=162
2 mũ x – 15=17
(7 mũx -11)mũ 3 = 5 mũ 2+200
x mũ 10=x

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Gerda 1 year 2020-11-14T04:05:46+00:00 2 Answers 113 views 0

Answers ( )

    0
    2020-11-14T04:06:46+00:00

    Giải thích các bước giải:

    `2.3 ^ x=162`
    `=>3^x=162:2`
    `=>3^x=81`
    `=>3^x=3^4`
    `=>x=4`
    `2 ^ x – 15=17`
    `=>2^x=17+15`
    `=>2^x=32`
    `=>2^x=2^5`
    `=>x=5`
    `(7.x-11)^3=5^2. 2^5+200`
    `=>(7.x – 11)^3=25 . 32+200`
    `=>(7.x – 11)^3=800+200`
    `=>(7.x – 11)^3=1000`
    `=>(7.x – 11)^3=10^3`
    `=>7.x – 11=10`
    `=>7.x = 10+11`
    `=>7.x=21`
    `=>x=21:7`
    `=>x=3`

    `x^10=x`
    `=>x^10-x=0`
    `=>x^9 . x-x.1=0`
    `=>x.(x^9 -1)=0`
    `=>`\(\left[ \begin{array}{l}x=0\\x^9 – 1=0\end{array} \right.\) 
    `=>`\(\left[ \begin{array}{l}x=0\\x^9=0+1\end{array} \right.\) 
    `=>`\(\left[ \begin{array}{l}x=0\\x^9=1\end{array} \right.\) 
    `=>`\(\left[ \begin{array}{l}x=0\\x^9=1^9\end{array} \right.\) 
    `=>`\(\left[ \begin{array}{l}x=0\\x=1\end{array} \right.\) 

    0
    2020-11-14T04:07:01+00:00

    a) 3^x=162

    2.3∧X=2.3∧4

    ⇒x=4

    b)2∧x -15=17

     2∧x=32

    2∧X=2∧5

    ⇒x=5

    (7x-11)∧3=5∧2+200

    (7x-11)∧3=25.32+200

    (7x-11)∧3=1000

    (7x-11)∧3=10∧3

    7x-11=10

    7x=21

    x=3

    x∧10=x 

    ⇒x∧10-x=0

    ⇒x.(x∧9-1)=0

    TH1:⇒x=0

    TH2:⇒x∧9-1=0⇒x=1

    Vậy x=0 hoặc x=1

     

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