Làm ơn giúp mik vs ạ

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Làm ơn giúp mik vs ạ
lam-on-giup-mik-vs-a

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Verity 4 years 2020-10-29T04:58:17+00:00 1 Answers 67 views 0

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  1. Giakhanh
    0
    2020-10-29T04:59:40+00:00
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    Giải thích các bước giải:

    $a) (x-47)-235=7^{13}:7^{10}$

    $⇔x-47-235=7^3$

    $⇔x-282=343$

    $⇔x=625$

    $\text{Vậy $x=625$}$

    $b)114-(2x-6)^2:18=102$

    $⇔(2x-6)^2:18=12$

    $⇔4x^2-24x+36=12×18=216$

    $⇔4(x^2-6x+9)=216$

    $⇔x^2-6x+9=54$

    $⇔$ \(\left[ \begin{array}{l}x=3-3\sqrt{6}\\x=3+3\sqrt{6}\end{array} \right.\)

    $\text{Vậy $x∈\{3-3\sqrt{6};3+3\sqrt{6}\}$}$

    $c)5^2:2^x=20^2$

    $⇔25:2^x=400$

    $⇔2^x=25:400$

    $⇔2^x=0,0625$

    $⇔2^x=2^{-4}$

    $⇔x=-4$

    $\text{Vậy $x=-4$}$

    $d)7.3^x+20.3^x=3^{35}$

    $⇔3^x(7+20)=3^{35}$

    $⇔3^x.3^3=3^{35}$

    $⇔3^x=3^{35}:3^3$

    $⇔3^x=3^{32}$

    $⇔x=32$

    $\text{Vậy $x=32$}$

    $e)124+(x-8)=210$

    $⇔124+x-8=210$

    $⇔x+116=210$

    $⇔x=210-116$

    $⇔x=94$

    $\text{Vậy $x=94$}$

    Học tốt!!!

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