## |3x-2|=5 3\4+1\4:x=-2 {2\3} ²:{-8} – {-1\4+9\20}:9\5

Question

|3x-2|=5
3\4+1\4:x=-2
{2\3} ²:{-8} – {-1\4+9\20}:9\5

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3 years 2021-05-14T12:04:24+00:00 2 Answers 13 views 0

1. | 3x – 2 | = 5

⇔ $$\left[ \begin{array}{l}3x – 2 = 5\\3x – 2 = -5\end{array} \right.$$

⇔ $$\left[ \begin{array}{l}3x = 7\\3x = – 3\end{array} \right.$$

⇔ $$\left[ \begin{array}{l}x = 7/3\\x = – 1\end{array} \right.$$

Vậy , x ∈ { 7/3 ; – 1 }

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3/4 + 1/4 : x = – 2

⇔ 1/4 : x      = – 2 – 3/4

⇔ 1/4 : x      = -11/4

⇔         x      = -11/4 : 1/4

⇔          x      = -11

Vậy , x = -11

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( 2/3 )^2 : ( – 8 ) – ( – 1/4 + 9/20 ) : 9/5

= 4/9 : ( – 8 ) – 1/5 : 9/5

= -1/18 – 1/9

= -1/6

2. Đáp án:

ở dưới

nếu thấy hay thì cho mình xin

– 5 sao

– cám ơn

– hay nhất

Giải thích các bước giải:

|3x-2|=5

trường hợp 1 :

3x – 2 = 5

3x       = 5 + 2

3x       = 7

x        = 7 : 3

x        = $\frac{7}{3}$

trường hợp 2 :

3x – 2 = -5

3x       = -5 + 2

3x       = -3

x        = -3 : 3

x       = -1

vậy x ∈ { $\frac{7}{3}$ ; -1 }

$\frac{3}{4}$+$\frac{1}{4}$x=-2

$\frac{1}{4}$x = -2 – $\frac{3}{4}$

$\frac{1}{4}$x = $\frac{-11}{4}$

x = $\frac{-11}{4}$ : $\frac{1}{4}$

x= -11

vây x = -11

($\frac{2}{3}$) 2 : {-8} – {$\frac{-1}{4}$+$\frac{9}{20}$}:$\frac{9}{5}$

=$\frac{4}{9}$ . $\frac{-1}{8}$ – { $\frac{-5}{20}$ + $\frac{9}{20}$ . $\frac{5}{9}$

= $\frac{-4}{72}$ – $\frac{1}{5}$ . $\frac{5}{9}$

= $\frac{-1}{18}$ – $\frac{2}{18}$

= $\frac{1}{18}$