\(\dfrac{1}{2}\left(x-2\right)+\dfrac{1}{3}\left(2-x\right)=x\\ \Leftrightarrow\dfrac{1}{2}\left(x-2\right)-\dfrac{1}{3}\left(x-2\right)=x\\ \Leftrightarrow\left(x-2\right).\left(\dfrac{1}{2}-\dfrac{1}{3}\right)=x\\ \Leftrightarrow\left(x-2\right).\left(\dfrac{3-2}{6}\right)=x\\ \Leftrightarrow\left(x-2\right).\dfrac{1}{6}=x\\ \Leftrightarrow\dfrac{1}{6}x-\dfrac{1}{3}-x=0\\ \Leftrightarrow\left(\dfrac{1}{6}-1\right)x=\dfrac{1}{3}\\ \Leftrightarrow\left(\dfrac{1-6}{6}\right)x=\dfrac{1}{3}\\ \Leftrightarrow\dfrac{-5}{6}x=\dfrac{1}{3}\\ \Leftrightarrow x=\dfrac{1}{3}:\left(-\dfrac{5}{6}\right)\\ \Leftrightarrow x=-\dfrac{2}{5}\)

Vậy \(x=-\dfrac{2}{5}\)

x= \(\dfrac{7\pm\sqrt{37}}{3}\) nha

\(3^x+4\cdot3^{x-2}=333\)

\(\Rightarrow3^{x-2+2}+4\cdot3^{x-2}=333\)

\(\Rightarrow3^{x-2}\cdot\left(3^2+4\right)=333\)

\(\Rightarrow3^{x+2}\cdot\left(9+4\right)=333\)

\(\Rightarrow3^{x+2}\cdot13=333\)

\(\Rightarrow3^{x+2}=333:13\)

\(\Rightarrow3^{x+2}=\dfrac{333}{13}\)

Không có x nào thỏa mãn

⇒ x ∈ ∅

Mk cần gấp á. Ai hỗ trợ mk với

ĐKXĐ : 2x \(\ge\)0 <=> x \(\ge\)0

| 7 + x | = 2x <=> \(\orbr{\begin{cases}7+x=2x\\7+x=-2x\end{cases}}\)

                     <=> \(\orbr{\begin{cases}x=7\\x=\frac{-7}{3}\end{cases}}\)( KTMĐK)

Vậy x = 7 

giúp mik nhanh với ah mik cần gấp

0,25 x 3 + 1 : 4 x 7

= 0,25 (3+7)

= 0,25 x 10

= 2,5

X x 1.2 + X x 1.8 = 45

X [1(2+8)] = 45

X [1 x 10] = 45

X x 10 = 45

        X = 45 : 10

        X = 4,5

Bài 9:

\(\Leftrightarrow\dfrac{x}{5}=\dfrac{y}{-3}=\dfrac{z}{-17}=\dfrac{t}{9}=-2\)

=>x=-10; y=6; z=34; t=-18

Bài 10:

\(\Leftrightarrow\dfrac{8}{x}=\dfrac{y}{21}=\dfrac{40}{z}=\dfrac{16}{t}=\dfrac{u}{111}=\dfrac{4}{3}\)

=>x=6; y=28; z=30; t=12; u=148

\(6\cdot x+9=15\)

\(\Rightarrow6\cdot x=15-9\)

\(\Rightarrow6\cdot x=6\)

\(\Rightarrow x=\dfrac{6}{6}=1\)

_______________

\(43+2x=49\)

\(\Rightarrow2x=49-43\)

\(\Rightarrow2x=6\)

\(\Rightarrow x=\dfrac{6}{2}=3\)

____________

\(x:2+5=11\)

\(\Rightarrow x:2=11-5\)

\(\Rightarrow x:2=6\)

\(\Rightarrow x=6\cdot2=12\)

______________

\(77-11x=0\)

\(\Rightarrow11x=77\)

\(\Rightarrow x=\dfrac{77}{11}\)

\(\Rightarrow x=7\)

_______________

\(12-4:x=8\)

\(\Rightarrow4:x=12-8\)

\(\Rightarrow4:x=4\)

\(\Rightarrow x=\dfrac{4}{4}=1\)

_____________

\(x:3+8=11\)

\(\Rightarrow x:3=11-8\)

\(\Rightarrow x:3=3\)

\(\Rightarrow x=3\cdot3=9\)

a: 6x+9=15

=>6x=6

=>x=1

b: 2x+43=49

=>2x=6

=>x=3

c: x:2+5=11

=>x:2=6

=>x=12

d: 77-11x=0

=>7-x=0

=>x=7

e: 12-4:x=8

=>4:x=4

=>x=1

f: x:3+8=11

=>x:3=3

=>x=9

1.A
2.A
3.B
4.C
5.B
6.C
7.A
8.A
9.B
10.A
11.B
12.A
13.C
14.B
15.B
16.A
17.A
18.A
19.A
20.C

khó quá ??????????????????????????????????

a) (-2) . ( x+7 ) + (-5) = 7 

<=>(-2).(x+7)=7+5

<=>x+7=12:(-2)

<=>x+7=-6

<=>x=(-6)-7

<=>x=-13

Vậy x=-13

b)(x+4) : (-7) = 14

<=>x+4=14 x (-7)

<=>x+4=-98

<=>x=-98-4

<=>x=-102

Vậy x= -102

c) 72 : ( x+5) - 4 = -12 

<=>72:(x+5)=(-12)+4

<=>x+5=72:(-8)

<=>x+5=-9

<=>x=-9-5

<=>x=-14

Vậy x= -14

d) (x+3) : (-6 ) + 12 = 8 

<=>(x+3) :(-6)=8-12

<=>x+3=(-4)x(-6)

<=>x+3=24

<=>x=24-3

<=>x=21

Vậy x= 21