Tìm X

a, 4/5+X=9/7

b, 5/4+x =3/8+5/12

2 câu trả lời

Gửi em! 

Giải thích các bước giải:

a, $\dfrac{4}{5}$ + $x$ = $\dfrac{9}{7}$

   $x$ = $\dfrac{9}{7}$ - $\dfrac{4}{5}$

   $x$ = $\dfrac{17}{35}$

b, $\dfrac{5}{4}$ + $x$ = $\dfrac{3}{8}$ + $\dfrac{5}{12}$

    $\dfrac{5}{4}$ + $x$ = $\dfrac{19}{24}$

    $x$ = $\dfrac{19}{24}$ - $\dfrac{5}{4}$

    $x$ = $\dfrac{-11}{24}$

$\dfrac{4}{5}$ + x = $\dfrac{9}{7}$

⇒ x = $\dfrac{9}{7}$ - $\dfrac{4}{5}$

⇒ x = $\dfrac{17}{35}$

Vậy x = $\dfrac{17}{35}$

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$\dfrac{5}{4}$ + x = $\dfrac{5}{12}$ + $\dfrac{3}{8}$

$\dfrac{5}{4}$ + x = $\dfrac{19}{24}$

⇒ x = $\dfrac{19}{24}$ - $\dfrac{5}{4}$

⇒ x = $\dfrac{-11}{24}$

Vậy x = $\dfrac{-11}{24}$

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