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

Toán Lớp 8: giải phương trình `1) {x + {2.(x – 1)}/5}/3 = 1 + {1 + x/{12}}/5` `2) x – {x/2 – {3 + x}/4}/2 = {2x – {10 – 7x}/3}/2 – x – 1`

Tháng Tám 9, 2022 Toán học 1 Comment 0 views

Toán Lớp 8: giải phương trình
1) {x + {2.(x – 1)}/5}/3 = 1 + {1 + x/{12}}/5
2) x – {x/2 – {3 + x}/4}/2 = {2x – {10 – 7x}/3}/2 – x – 1

Comments ( 1 )

  1. thanhthuythu
    thanhthuythu
    9 Tháng Tám, 2022 at 10:27 chiều
    Reply
    Giải đáp:
    1)   $x=\dfrac{80}{27}$
    2)   $x=\dfrac{73}{7}$
     
    Lời giải và giải thích chi tiết:
    1)   $\dfrac{x+\dfrac{2\left( x-1 \right)}{5}}{3}=1+\dfrac{1+\dfrac{x}{12}}{5}$
    $\Leftrightarrow \dfrac{x+\dfrac{2\left( x-1 \right)}{5}}{3}=\dfrac{5+1+\dfrac{x}{12}}{5}$
    $\Leftrightarrow 5\left[ x+\dfrac{2\left( x-1 \right)}{5} \right]=3\left( 6+\dfrac{x}{12} \right)$
    $\Leftrightarrow 5x+2\left( x-1 \right)=18+\dfrac{x}{4}$
    $\Leftrightarrow \dfrac{27}{4}x=20$
    $\Leftrightarrow x=\dfrac{80}{27}$
     
    2)   $x-\dfrac{\dfrac{x}{2}-\dfrac{3+x}{4}}{2}=\dfrac{2x-\dfrac{10-7x}{3}}{2}-x-1$
    $\Leftrightarrow \dfrac{2x-\left( \dfrac{x}{2}-\dfrac{3+x}{4} \right)}{2}=\dfrac{2x-\dfrac{10-7x}{3}-2x-2}{2}$
    $\Leftrightarrow 2x-\left( \dfrac{x}{2}-\dfrac{3}{4}-\dfrac{x}{4} \right)=2x-\left( \dfrac{10}{3}-\dfrac{7}{3}x \right)-2x-2$
    $\Leftrightarrow 2x-\dfrac{x}{2}+\dfrac{3}{4}+\dfrac{x}{4}=2x-\dfrac{10}{3}+\dfrac{7}{3}x-2x-2$
    $\Leftrightarrow -\dfrac{7}{12}x=-\dfrac{73}{12}$
    $\Leftrightarrow x=\dfrac{73}{7}$

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

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