2 x – 1/5 + 1/3 x = 1 4/3 x +2/5 – 1/5 x = 1 x+2/3 + 1/2 x = 1 28/08/2021 Bởi Valentina 2 x – 1/5 + 1/3 x = 1 4/3 x +2/5 – 1/5 x = 1 x+2/3 + 1/2 x = 1
a) $2x-\dfrac{1}{5}+\dfrac{1}{3}x=1$ $(2x+\dfrac{1}{3}x)-\dfrac{1}{5}=1$ $\dfrac{7}{3}x=1+\dfrac{1}{5}$ $\dfrac{7}{3}x=\dfrac{6}{5}$ ⇒ $x=\dfrac{6}{5}:\dfrac{7}{3}$ ⇒ $x=\dfrac{6}{5}.\dfrac{3}{7}=\dfrac{18}{35}$ b) $\dfrac{4}{3}x+\dfrac{2}{5}-\dfrac{1}{5}x=1$ $(\dfrac{4}{3}x-\dfrac{1}{5}x)+\dfrac{2}{5}=1$ $\dfrac{17}{15}x=\dfrac{3}{5}$ ⇒ $x=\dfrac{3}{5}:\dfrac{17}{15}$ ⇒ $x=\dfrac{3}{5}.\dfrac{15}{17}=\dfrac{9}{17}$ c) $x+\dfrac{2}{3}+\dfrac{1}{2}x=1$ $(x+\dfrac{1}{2}x)+\dfrac{2}{3}=1$ $\dfrac{3}{2}x=\dfrac{1}{3}$ ⇒ $x=\dfrac{1}{3}:\dfrac{3}{2}$ ⇒ $x=\dfrac{1}{3}.\dfrac{2}{3}=\dfrac{2}{9}$ Bình luận
a) $2x-\dfrac{1}{5}+\dfrac{1}{3}x=1$
$(2x+\dfrac{1}{3}x)-\dfrac{1}{5}=1$
$\dfrac{7}{3}x=1+\dfrac{1}{5}$
$\dfrac{7}{3}x=\dfrac{6}{5}$
⇒ $x=\dfrac{6}{5}:\dfrac{7}{3}$
⇒ $x=\dfrac{6}{5}.\dfrac{3}{7}=\dfrac{18}{35}$
b) $\dfrac{4}{3}x+\dfrac{2}{5}-\dfrac{1}{5}x=1$
$(\dfrac{4}{3}x-\dfrac{1}{5}x)+\dfrac{2}{5}=1$
$\dfrac{17}{15}x=\dfrac{3}{5}$
⇒ $x=\dfrac{3}{5}:\dfrac{17}{15}$
⇒ $x=\dfrac{3}{5}.\dfrac{15}{17}=\dfrac{9}{17}$
c) $x+\dfrac{2}{3}+\dfrac{1}{2}x=1$
$(x+\dfrac{1}{2}x)+\dfrac{2}{3}=1$
$\dfrac{3}{2}x=\dfrac{1}{3}$
⇒ $x=\dfrac{1}{3}:\dfrac{3}{2}$
⇒ $x=\dfrac{1}{3}.\dfrac{2}{3}=\dfrac{2}{9}$
Đáp án:
a) x = 18/35
b) x =9/17
c) x = 2/9
Giải thích các bước giải:
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