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20 tháng 3 2023

a)

`2x-3=2-x`

`<=>2x+x=2+3`

`<=>3x=5`

`<=>x=5/3`

b)

`3x+3=7+5x`

`<=>3x-5x=7-3`

`<=>-2x=4`

`<=>x=-2`

c)

`7x-3=3x+13`

`<=>7x-3x=13+3`

`<=>4x=16`

`<=>x=4`

d)

`(5x-2)/3=(5-3x)/2`

`<=>10x-4=15-9x`

`<=>10x+9x=15+4`

`<=>19x=19`

`<=>x=1`

11 tháng 1 2023

Bài `1:`

`h)(3/4x-1)(5/3x+2)=0`

`=>[(3/4x-1=0),(5/3x+2=0):}=>[(x=4/3),(x=-6/5):}`

______________

Bài `2:`

`b)3x-15=2x(x-5)`

`<=>3(x-5)-2x(x-5)=0`

`<=>(x-5)(3-2x)=0<=>[(x=5),(x=3/2):}`

`d)x(x+6)-7x-42=0`

`<=>x(x+6)-7(x+6)=0`

`<=>(x+6)(x-7)=0<=>[(x=-6),(x=7):}`

`f)x^3-2x^2-(x-2)=0`

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

`<=>(x-2)(x^2-1)=0<=>[(x=2),(x^2=1<=>x=+-2):}`

`h)(3x-1)(6x+1)=(x+7)(3x-1)`

`<=>18x^2+3x-6x-1=3x^2-x+21x-7`

`<=>15x^2-23x+6=0<=>15x^2-5x-18x+6=0`

`<=>(3x-1)(5x-1)=0<=>[(x=1/3),(x=1/5):}`

`j)(2x-5)^2-(x+2)^2=0`

`<=>(2x-5-x-2)(2x-5+x+2)=0`

`<=>(x-7)(3x-3)=0<=>[(x=7),(x=1):}`

`w)x^2-x-12=0`

`<=>x^2-4x+3x-12=0`

`<=>(x-4)(x+3)=0<=>[(x=4),(x=-3):}`

11 tháng 1 2023

`m)(1-x)(5x+3)=(3x-7)(x-1)`

`<=>(1-x)(5x+3)+(1-x)(3x-7)=0`

`<=>(1-x)(5x+3+3x-7)=0`

`<=>(1-x)(8x-4)=0<=>[(x=1),(x=1/2):}`

`p)(2x-1)^2-4=0`

`<=>(2x-1-2)(2x-1+2)=0`

`<=>(2x-3)(2x+1)=0<=>[(x=3/2),(x=-1/2):}`

`r)(2x-1)^2=49`

`<=>(2x-1-7)(2x-1+7)=0`

`<=>(2x-8)(2x+6)=0<=>[(x=4),(x=-3):}`

`t)(5x-3)^2-(4x-7)^2=0`

`<=>(5x-3-4x+7)(5x-3+4x-7)=0`

`<=>(x+4)(9x-10)=0<=>[(x=-4),(x=10/9):}`

`u)x^2-10x+16=0`

`<=>x^2-8x-2x+16=0`

`<=>(x-2)(x-8)=0<=>[(x=2),(x=8):}`

a: \(\Leftrightarrow7\left(7-3x\right)+12\left(5x+2\right)=84\left(x+13\right)\)

\(\Leftrightarrow49-21x+60x+24=84x+1092\)

\(\Leftrightarrow39x-84x=1092-73\)

=>-45x=1019

hay x=-1019/45

b: \(\Leftrightarrow21\left(x+3\right)-14=4\left(5x+9\right)-7\left(7x-9\right)\)

=>21x+63-14=20x+36-49x+63

=>21x+49=-29x+99

=>50x=50

hay x=1

c: \(\Leftrightarrow7\left(2x+1\right)-3\left(5x+2\right)=21x+63\)

=>14x+7-15x-6-21x-63=0

=>-22x-64=0

hay x=-32/11

d: \(\Leftrightarrow35\left(2x-3\right)-15\left(2x+3\right)=21\left(4x+3\right)-17\cdot105\)

=>70x-105-30x-45=84x+63-1785

=>40x-150-84x+1722=0

=>-44x+1572=0

hay x=393/11

19 tháng 2 2022

a, msc 12.7=84 

Chuyển vế về =0 rồi làm

b,msc 28

c,làm tương tự

12 tháng 8 2021

undefined

12 tháng 4 2022

g.\(\dfrac{1-3x}{6}+x-1=\dfrac{x+2}{2}\)

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

\(\Leftrightarrow\left(1-3x\right)+6\left(x-1\right)=3\left(x+2\right)\)

\(\Leftrightarrow1-3x+6x-6=3x+6\)

\(\Leftrightarrow-5=6\left(vô.lí\right)\)

Vậy pt vô nghiệm

12 tháng 4 2022

h.\(\dfrac{3\left(2x+1\right)}{4}-5-\dfrac{3x+2}{10}=\dfrac{2\left(3x-1\right)}{5}\)

\(\Leftrightarrow\dfrac{15\left(2x+1\right)-100-2\left(3x+2\right)}{20}=\dfrac{8\left(3x-1\right)}{20}\)

\(\Leftrightarrow15\left(2x+1\right)-100-2\left(3x+2\right)=8\left(3x-1\right)\)

\(\Leftrightarrow30x+15-100-6x-4=24x-8\)

\(\Leftrightarrow-89=-8\left(vô.lí\right)\)

Vậy pt vô nghiệm

bài 2 giải các phương trình saub,\(\dfrac{2\left(3-7x\right)}{1+x}=\dfrac{1}{2}\)               m,\(\dfrac{3x-1}{x+1}=\dfrac{2x+1}{x-1}\)d,\(\dfrac{3x-14}{x+5}=\dfrac{2}{3}\)                   p,\(\dfrac{4x+7}{x-1}=\dfrac{12x+5}{3x+4}\)f,\(\dfrac{6}{x}-1=\dfrac{2x-3}{3}\)               r,\(\dfrac{1}{x+3}+\dfrac{1}{x-1}=\dfrac{10}{\left(x+3\right)\left(x-1\right)}\)h,\(\dfrac{1}{x-2}+3=\dfrac{x-3}{2-x}\)       ...
Đọc tiếp

bài 2 giải các phương trình sau

b,\(\dfrac{2\left(3-7x\right)}{1+x}=\dfrac{1}{2}\)               m,\(\dfrac{3x-1}{x+1}=\dfrac{2x+1}{x-1}\)

d,\(\dfrac{3x-14}{x+5}=\dfrac{2}{3}\)                   p,\(\dfrac{4x+7}{x-1}=\dfrac{12x+5}{3x+4}\)

f,\(\dfrac{6}{x}-1=\dfrac{2x-3}{3}\)               r,\(\dfrac{1}{x+3}+\dfrac{1}{x-1}=\dfrac{10}{\left(x+3\right)\left(x-1\right)}\)

h,\(\dfrac{1}{x-2}+3=\dfrac{x-3}{2-x}\)         t,\(\dfrac{3x}{x-2}-\dfrac{x}{x-5}=\dfrac{3x}{\left(x-2\right)\left(5-x\right)}\)

j,\(\dfrac{5}{3x+2}=2x-1\)              u,\(\dfrac{x+3}{x+1}+\dfrac{x-2}{x}=\dfrac{2\left(x^2+x-1\right)}{x\left(x+1\right)}\)

w,\(\dfrac{5x}{2x+2}+1=-\dfrac{6}{x+1}\)         s, \(\dfrac{6}{x-1}-\dfrac{4}{x-3}=\dfrac{2x}{\left(x-1\right)\left(x-3\right)}\)

ơ,\(\dfrac{1}{x-1}+\dfrac{2}{x+1}=\dfrac{x}{x^2-1}\)          v,\(\dfrac{x}{2\left(x-3\right)}+\dfrac{x}{2\left(x+1\right)}=\dfrac{2x}{\left(x+1\right)\left(x-3\right)}\)

z,\(\dfrac{1}{x-1}-\dfrac{3x^2}{x^3-1}=\dfrac{2x}{x^2+x+1}\)             ư,\(\dfrac{x+2}{x-2}-\dfrac{-2}{x^2-2x}=\dfrac{1}{x}\)

o,\(x+\dfrac{1}{x}=x^2+\dfrac{1}{x^2}\)          ô,\(1-\dfrac{1}{1-x}=\dfrac{x^2}{x^2-1}\)       zz,\(\dfrac{12}{8+x^3}=1+\dfrac{1}{x+2}\)

2
13 tháng 1 2023

Bạn chia nhỏ các phần ra nhé.

13 tháng 1 2023

uh mk biết lần sau mk rút kinh nghiệm

AH
Akai Haruma
Giáo viên
31 tháng 3 2022

Lời giải:
a. $2x+7>0$

$\Leftrightarrow x> \frac{-7}{2}$

b. 

$-5x+12<17$

$\Leftrightarrow -5x< 5$

$\Leftrightarrow 5+5x>0$

$\Leftrightarrow 5x>-5$

$\Leftrightarrow x>-1$

c. 

$-3x+5>-5x+2$

$\Leftrightarrow (-3x+5)-(-5x+2)>0$

$\Leftrightarrow 2x+3>0$

$\Leftrightarrow x> \frac{-3}{2}$

d.

$\frac{x}{2}+3< 7$

$\Leftrightarrow \frac{x}{2}< 4$

$\Leftrightarrow x< 8$

 

 

27 tháng 2 2021

`(2x)/(3x^2-x+2)-(7x)/(3x^2+5x+2)=1(x ne -1,-2/3)`

Đặt `a=3x^2+2x+2(a>=5/3)`

`pt<=>(2x)/(a-3x)-(7x)/(a+3x)=1`

`=>2x(a+3x)-7x(a-3x)=a^2-9x^2`

`<=>2ax+6x^2-7ax+21x^2=a^2-9x^2`

`<=>-5ax+27x^2=a^2-9x^2`

`<=>a^2-36x^2+5ax=0`

`<=>a^2-4ax+9ax-36x^2=0`

`<=>a(a-4x)+9x(a-4x)=0`

`<=>(a-4x)(a+9x)=0`

`+)a=4x`

`=>3x^2+2x+2=4x`

`=>3x^2-2x+2=0`

`=>x^2-2/3x+2/3=0`

`=>(x-1/3)^2+5/9=0` vô lý

`+)a+9x=0`

`=>3x^2+2x+2+9x=0`

`=>3x^2+11x+2=0`

`=>x^2+11/3x+2/3=0`

`=>x=(-11+-\sqrt{97})/6`

27 tháng 2 2021

ĐKXĐ: \(x\ne-1;x\ne-\dfrac{2}{3}\)

Ta có: \(\dfrac{2x}{3x^2-x+2}-\dfrac{7x}{3x^2+5x+2}=1\)(1)

\(\Leftrightarrow\dfrac{2}{3x-1+\dfrac{2}{x}}-\dfrac{7}{3x+5+\dfrac{2}{x}}=1\)

Đặt: \(3x+\dfrac{2}{x}=a\)  (x khác 0) thì pt(1) trở thành:

\(\dfrac{2}{a-1}-\dfrac{7}{a+5}=1\)

\(\Leftrightarrow\dfrac{2\left(a+5\right)-7\left(a-1\right)}{\left(a-1\right)\left(a+5\right)}=1\)

\(\Leftrightarrow2\left(a+5\right)-7\left(a-1\right)=\left(a-1\right)\left(a+5\right)\)

\(\Leftrightarrow-5a+17=a^2+4a-5\)

\(\Leftrightarrow a^2+4a+5-5-17=0\)

\(\Leftrightarrow a^2+9a-22=0\)

\(\Leftrightarrow\left(a-2\right)\left(a+11\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}a=2\\a=-11\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x+\dfrac{2}{x}=2\\3x+\dfrac{2}{x}=-11\end{matrix}\right.\)

Vì \(\left\{{}\begin{matrix}3x^2+2-2x\ne0\\3x^2+11x+2\ne0\end{matrix}\right.\)

=> PT vô nghiệm 

Ủa hình như sai:vvv

 

 

4 tháng 2 2022

\(i.\dfrac{\left(2x+1\right)^2}{5}-\dfrac{\left(x-1\right)^2}{3}=\dfrac{7x^2-14x-5}{15}\)

\(\Leftrightarrow\dfrac{4x^2+4x+1}{5}-\dfrac{x^2-2x+1}{3}=\dfrac{7x^2-14x-5}{15}\)

\(\Leftrightarrow\dfrac{12x^2+12x+3}{15}-\dfrac{5x^2-10x+5}{15}=\dfrac{7x^2-14x-5}{15}\)

\(\Leftrightarrow12x^2+12x+3-5x^2+10x-5=7x^2-14x-5\)

\(\Leftrightarrow36x=-3\)

\(\Leftrightarrow x=-\dfrac{1}{12}\)

4 tháng 2 2022

\(k.x+\dfrac{2x+\dfrac{x-1}{5}}{3}=1-\dfrac{3x-\dfrac{1-2x}{3}}{5}\)

\(\Leftrightarrow\dfrac{15x}{15}+\dfrac{10x+x-1}{15}=\dfrac{15}{15}-\dfrac{9x-1+2x}{15}\)

\(\Leftrightarrow15x+9x-1=14-7x\)

\(\Leftrightarrow31x=15\)

\(\Leftrightarrow x=\dfrac{15}{31}\)

a: =>10x-4=15-9x

=>19x=19

hay x=1

b: \(\Leftrightarrow3\left(10x+3\right)=36+4\left(8x+6\right)\)

=>30x+9=36+32x+24

=>30x-32x=60-9

=>-2x=51

hay x=-51/2

c: \(\Leftrightarrow2x+\dfrac{6}{5}=5-\dfrac{13}{5}-x\)

=>3x=6/5

hay x=2/5

d: \(\Leftrightarrow\dfrac{7x}{8}-\dfrac{5\left(x-9\right)}{1}=\dfrac{20x+1.5}{6}\)

\(\Leftrightarrow21x-120\left(x-9\right)=4\left(20x+1.5\right)\)

=>21x-120x+1080=80x+60

=>-179x=-1020

hay x=1020/179

e: \(\Leftrightarrow5\left(7x-1\right)+60x=6\left(16-x\right)\)

=>35x-5+60x=96-6x

=>95x+6x=96+5

=>x=1

f: \(\Leftrightarrow6\left(x+4\right)+30\left(-x+4\right)=10x-15\left(x-2\right)\)

=>6x+24-30x+120=10x-15x+30

=>-24x+96=-5x+30

=>-19x=-66

hay x=66/19