`a)2x^2+3(x-1)(x+1)=5x(x+1)`

`<=>2x^2+3x^2-3=5x^2+5x`

`<=>5x=-3`

`<=>x=-3/5`

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`b)(x-3)^3+3-x=0` nhỉ?

`<=>(x-3)^3-(x-3)=0`

`<=>(x-3)(x^2-1)=0`

`<=>[(x=3),(x^2=1<=>x=+-1):}`

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`c)5x(x-2000)-x+2000=0`

`<=>5x(x-2000)-(x-2000)=0`

`<=>(x-2000)(5x-1)=0`

`<=>[(x=2000),(x=1/5):}`

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`d)3(2x-3)+2(2-x)=-3`

`<=>6x-9+4-2x=-3`

`<=>4x=2`

`<=>x=1/2`

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`e)x+6x^2=0`

`<=>x(1+6x)=0`

`<=>[(x=0),(x=-1/6):}`

\(a,\Rightarrow1485,925-x-225=755\)

\(\Rightarrow1485,925-x=755+225\)

\(\Rightarrow1485,925-x=980\)

\(\Rightarrow x=1485,925-980\)

\(\Rightarrow x=505,925\)

\(b,\Rightarrow\left(9-5,34\right):x=3\)

\(\Rightarrow3,66:x=3\)

\(\Rightarrow x=3,66:3\)

\(\Rightarrow x=1,22\)

a) <=> |-5X| =3X +16 

DK : X >-16/3

-5X = 3X +16 HOAC -5X =-3X-16 

-8X = 16 HOAC -2X = -16 

X= -2 HOAC X= 8 

VẬY S= {-2; 8}

b) <=> 3X +X = 1+2

<=> 4X = 3

<=> X=3/4

VẬY S={3/4}   

c) DK : X> 10/4

-2X = 4X-10 HOAC -2X = -4X +10 

-6X = 10 HOAC 2X = 10

X= -5/3 (LOAI) HOAC X= 5 (NHAN)

VẬY S={5}

LƯU Ý: CÓ CHỮ " HOẶC" THÌ KHÔNG CẦN MŨI TÊN HAI CHIỀU 

-MÌNH CHỈ GHI CÁCH GIẢI THÔI NHÉ 

CHÚC BẠN HỌC TỐT .

\(5x\left(x-3\right)=x-3\)

\(\Rightarrow5x\left(x-3\right)-\left(x-3\right)=0\)

\(\Rightarrow\left(x-3\right)\left(5x-1\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-3=0\\5x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=\frac{1}{5}\end{cases}}}\)

Ta có:

x+2x+3x+...+100x=50

x.(1+2+3+...+100)=50

x.5050=50

x=\(\frac{1}{101}\)

\(x+2x+3x+...+100x=50\)

\(\Rightarrow5050x=50\)

\(\Rightarrow x=\frac{50}{5050}\)

\(\Rightarrow x=\frac{1}{101}\)

a) \(\left(\frac{3}{5}x-\frac{2}{3}x-x\right).\frac{1}{7}=\frac{-5}{21}\)

\(\Rightarrow\left(\frac{3}{5}-\frac{2}{3}-1\right).x=\frac{-5}{21}:\frac{1}{7}=\frac{-5}{3}\)

\(\Rightarrow\frac{-16}{15}.x=\frac{-5}{3}\Rightarrow x=\frac{-5}{3}:\frac{-16}{15}=\frac{25}{16}\)

b) \(\left(x-\frac{1}{4}\right)^2=\frac{1}{36}\)

\(\Rightarrow\left(x-\frac{1}{4}\right)^2=\left(±\frac{1}{6}\right)^2\)

\(\Rightarrow\orbr{\begin{cases}x-\frac{1}{4}=\frac{1}{6}\\x-\frac{1}{4}=\frac{-1}{6}\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{5}{12}\\x=\frac{1}{12}\end{cases}}\)

c) \(14-\left|\frac{3x}{2}-1\right|=9\)

\(\Rightarrow\left|\frac{3x}{2}-1\right|=14-9=5\)

\(\Rightarrow\orbr{\begin{cases}\frac{3x}{2}-1=5\\\frac{3x}{2}-1=-5\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}\frac{3x}{2}=6\\\frac{3x}{2}=-4\end{cases}}\Rightarrow\orbr{\begin{cases}3x=12\\3x=-8\end{cases}}\Rightarrow\orbr{\begin{cases}x=4\\x=\frac{-8}{3}\end{cases}}\)

x + 2x + 3x = 180

x(1 + 2 + 3) = 180

x . 6 = 180

x = 180 : 6

x = 30.

[3x - 8] + 6 = 25

3x - 8 = 25 - 6

3x - 8 = 19

3x = 27

x = 27 : 3

x = 9.

x + 2x + 3x = 180

6x = 180

x = 180 : 6

x = 30

Vậy x = 30.

(3x - 8) + 6 = 25

3x - 8 = 25 - 6

3x - 8 = 19

3x = 19 + 8

3x = 27

x = 27 : 3

x = 9

Vậy x = 9.

\(x+2x+3x=180\)

\(\left(1+2+3\right)\times x=180\)

\(6\times x=180\)

\(x=180:6\)

\(x=30\)

\(\left(3x-8\right)+6=25\)

\(3x-8=25-6\)

\(3x=19+8\)

\(3x=27\)

\(x=27:3\)

\(x=9\)

Học tốt

Bài 2:

\(2x^3+6x^2=x^2+3x\)

\(\Rightarrow2x^3+6x^2-x^2-3x=0\)

\(\Rightarrow2x^3+5x^2-3x=0\)

\(\Rightarrow x\left(2x^2+5x-3\right)=0\)

\(\Rightarrow x\left(2x^2-x+6x-3\right)=0\)

\(\Rightarrow x\left[x\left(2x-1\right)+3\left(2x-1\right)\right]=0\)

\(\Rightarrow x\left(x+3\right)\left(2x-1\right)=0\)

=>x=0 hoặc x=-3 hoặc x=1/2

1)

\(\Leftrightarrow x^2-2x-3x+6=0\)

\(\Leftrightarrow x\left(x-2\right)-3\left(x-2\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(x-3\right)=0\)

Tới đây b cho từng cái = 0 rồi giải ra tìm x nha :)

Cảm ơn 2 bạn nhé