Đáp án:

\(1/\\ a,\ x=\dfrac{-5}{2}\\ b,\ x=\dfrac{-86}{55}\\ c,\ x=\dfrac{-1}{2}\ \text{hoặc}\ x=\dfrac{-5}{6}\\ d,\ x=4\)

Giải thích các bước giải:

\(1/\\ a,\ 3:x=-6:5\\ ⇔3:x=\dfrac{-6}{5}\\ ⇔x=3:\dfrac{-6}{5}\\ ⇔x=\dfrac{-5}{2}\\ \text{Vậy x = $\dfrac{-5}{2}$}\\ b,\ 2\dfrac{3}{4}x+3\dfrac{1}{2}=\dfrac{-4}{5}\\ ⇔\dfrac{11}{4}x+\dfrac{7}{2}=\dfrac{-4}{5}\\ ⇔\dfrac{11}{4}x=\dfrac{-4}{5}-\dfrac{7}{2}\\ ⇔\dfrac{11}{4}x=\dfrac{-43}{10}\\ ⇔x=\dfrac{-43}{10}:\dfrac{11}{4}\\ ⇔x=\dfrac{-86}{55}\\ \text{Vậy x = $\dfrac{-86}{55}$}\\ c,\ \bigg|x+\dfrac{2}{3}\bigg|-\dfrac{1}{6}=0\\ ⇔\bigg|x+\dfrac{2}{3}\bigg|=\dfrac{1}{6}\\ ⇔\left[ \begin{array}{l}x+\dfrac{2}{3}=\dfrac{1}{6}\\x+\dfrac{2}{3}=\dfrac{-1}{6}\end{array} \right.\ ⇔\left[ \begin{array}{l}x=\dfrac{-1}{2}\\x=\dfrac{-5}{6}\end{array} \right.\\ \text{Vậy x = $\dfrac{-1}{2}$ hoặc x = $\dfrac{-5}{6}$}\\ d,\ 2^{3}:4.2^{x+1}=64\\ ⇔8:4.2^{x+1}=64\\ ⇔2.2^{x+1}=64\\ ⇔2^{x+1}=64:2\\ ⇔2^{x+1}=32\\ ⇔2^{x+1}=2^{5}\\ ⇔x+1=5\\ ⇔x=5-1=4\\ \text{Vậy x = 4}\)

chúc em học tốt!

Bài $1$

$a$) `3 : x = -6 : 5`

`⇔ x = 3 : {-6}/{5}`

`⇔ x = {-5}/2`

 Vậy `x={-5}/2`

$b$) `2 3/4 x + 3 1/2 = - 4/5`

`⇔ {11}/4.x + 7/2 = -4/5`

`⇔ {11x}/4 .x= {-43}/{10}`

`⇔ x = {-86}/{55}`

  Vậy `x = {-86}/{55}`

$c$) `|x + 2/3 | - 1/6 = 0`

`⇒` \(\left[ \begin{array}{l}x=\dfrac{-1}{2}\\x=\dfrac{-5}{6}\end{array} \right.\) 

  Vậy $x$ $∈$ `{{-1}/2;{-5}/6}`

$d$) `(2^3 : 4) .2^{x+1} = 64`

`⇔ 2 . 2^{x+1} = 2^6

$⇔ 2^{x+2} = 2^6$

$⇔ x = 4$

  Vậy $x=4$.