a)  x – 32 = − 5 − 17 ⇔ x – 32 = − 32 ⇔ x = − 32 + 32 ⇔ x = 0.

b)  16 – x = 21 – − 8 ⇔ 16 – x = 21 + 8 ⇔ 16 − x = 30 ⇔ − x = 30 − 16 ⇔ − x = 14 ⇔ x = − 14.

c)  106 − x = − 58 – 8 ⇔ 106 − x = − 66 ⇔ − x = − 66 − 106 ⇔ − x = − 172 ⇔ x = 172.

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a) Tìm số nguyên x, biết:

Với \(x\in Z\), ta có:

9 - x = 8 - (2x + 16)

<=> 9 - x = 8 - 2x - 16 

<=> 9 - x = -2x - 8

<=> x  = -17 (TM)

Vậy x = -17

b) Với \(x\in Z\), ta có:

18 - 2x = 21 - (3x - 5)

<=> 18 - 2x = 21 - 3x + 5

<=> 18 - 2x = 26 - 3x

<=> x = 8 (TM)

Vậy x = 8

a) Ta có: 9-x=8-(2x+16)

\(\Leftrightarrow9-x=8-2x-16\)

\(\Leftrightarrow9-x=-2x-8\)

\(\Leftrightarrow9-x+2x+8=0\)

\(\Leftrightarrow x+17=0\)

hay x=-17

Vậy: x=-17

b) Ta có: 18-2x=21-(3x-5)

\(\Leftrightarrow18-2x=21-3x+5\)

\(\Leftrightarrow18-2x+3x-26=0\)

\(\Leftrightarrow x-8=0\)

hay x=8

Vậy: x=8

\(1,\dfrac{x}{9}=-\dfrac{16}{36}\)

\(\Leftrightarrow36x=-16\times9\)

\(\Leftrightarrow36x=-144\)

\(\Leftrightarrow x=-144:36\)

\(\Leftrightarrow x=-4\)

\(2,\dfrac{7}{x}=\dfrac{21}{-39}\)

\(\Leftrightarrow21x=7\times\left(-39\right)\)

\(\Leftrightarrow21x=-273\)

\(\Leftrightarrow x=-273:21\)

\(\Leftrightarrow x=-13\)

\(3,\dfrac{x}{5}=\dfrac{6}{-10}\)

\(\Leftrightarrow-10x=5\times6\)

\(\Leftrightarrow-10x=30\)

\(\Leftrightarrow x=3\)

\(\frac{x}{12}=\frac{5}{4}\)l

\(\Rightarrow x=\frac{5.12}{4}\)

\(\Rightarrow x=15\)

\(\frac{-8}{x}=\frac{16}{6}\)

\(\Rightarrow x=\frac{-8.6}{16}\)

\(\Rightarrow x=-3\)

làm giúp mình 2 bài cuối nha bạn tks trước

\(\frac{-7}{21}=\frac{x}{9}\)

\(\Rightarrow x=\frac{-7.9}{21}\)

\(\Rightarrow x=-3\)

\(\frac{-x}{15}=\frac{7}{3}\)

\(\Rightarrow\frac{x}{-15}=\frac{7}{3}\)

\(\Rightarrow x=\frac{-15.7}{3}\)

\(\Rightarrow x=-35\)

\(\Leftrightarrow\dfrac{x}{-4}=\dfrac{21}{y}=\dfrac{z}{-80}=\dfrac{3}{4}\)

=>x=-3; y=28; z=-60

x = -3; y = 28; z = -60

x = 13