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26 tháng 9 2019

\(x\left(x+2\right)\left(x+4\right)\left(x+6\right)=9\)

\(\Leftrightarrow x\left(x+2\right)\left(x+4\right)\left(x+6\right)-9=0\)

Đặt \(A=x\left(x+2\right)\left(x+4\right)\left(x+6\right)-9\)

\(A=x\left(x+6\right)\left(x+2\right)\left(x+4\right)-9\)

\(=\left(x^2+6x\right)\left(x^2+6x+8\right)-9\)(1)

Đặt \(a=x^2+6x\)

\(\Rightarrow\left(1\right)=a\left(a+8\right)-9=a^2+8a-9\)

\(=\left(a+4\right)^2-25=\left(a+4-5\right)\left(a+4+5\right)\)

\(=\left(a-1\right)\left(a+9\right)=\left(x^2+6x-1\right)\left(x^2+6x+9\right)\)

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

\(pt\Leftrightarrow\left(x^2+6x-1\right)\left(x+3\right)^2=0\)

\(TH1:x^2+6x-1=0\)

\(\Leftrightarrow\left(x+3\right)^2-10=0\)

\(\Leftrightarrow\left(x+3\right)^2=10\)

\(\Leftrightarrow\orbr{\begin{cases}x+3=\sqrt{10}\\x+3=-\sqrt{10}\end{cases}}\Leftrightarrow x=\pm\sqrt{10}+3\)

\(TH2:\left(x+3\right)^2=0\Leftrightarrow x+3=0\Leftrightarrow x=-3\)

Vậy \(x\in\left\{\pm\sqrt{10}+3;-3\right\}\)

a: \(\Leftrightarrow\left(2-x\right)\left(x-3\right)+\left(x-1\right)\left(x+3\right)=-4x\)

\(\Leftrightarrow2x-6-x^2+3x+x^2+3x-x-3=-4x\)

=>7x-9=-4x

=>11x=9

hay x=9/11

b: \(\Leftrightarrow\left(5-x\right)\left(x-4\right)+\left(x+2\right)\left(x+4\right)=-3x\)

\(\Leftrightarrow5x-20-x^2+4x+x^2+6x+8=-3x\)

=>15x-12=-3x

=>18x=12

hay x=2/3

31 tháng 10 2023

\(x+2\dfrac{1}{4}=4\dfrac{5}{6}\)

\(x=4\dfrac{5}{6}-2\dfrac{1}{4}\)

\(x=4+\dfrac{5}{6}-2-\dfrac{1}{4}\)

\(x=2+\dfrac{7}{12}\)

\(x=\dfrac{31}{12}\)

_____________

\(9\dfrac{3}{5}-x=3\dfrac{3}{8}\)

\(x=9\dfrac{3}{5}-3\dfrac{3}{8}\)

\(x=9+\dfrac{3}{5}-3-\dfrac{3}{8}\)

\(x=6+\dfrac{9}{40}\)

\(x=\dfrac{249}{40}\)

31 tháng 10 2023

\(x+2\dfrac{1}{4}=4\dfrac{5}{6}\)

\(=>x+\dfrac{9}{4}=\dfrac{29}{6}\)

\(=>x=\dfrac{29}{6}-\dfrac{9}{4}=\dfrac{58}{12}-\dfrac{27}{12}\)

\(=>x=\dfrac{31}{12}\)

_______

\(9\dfrac{3}{5}-x=3\dfrac{3}{8}\)

\(=>\dfrac{48}{5}-x=\dfrac{27}{8}\)

\(=>x=\dfrac{48}{5}-\dfrac{27}{8}=\dfrac{384}{40}-\dfrac{135}{40}\)

\(=>x=\dfrac{249}{40}\)

28 tháng 1 2018

-7+x = 15

=> x = 15-(-7) = 22

2.x-10 = -26

=> 2.x = -26+10 = -16

=> x = -16 : 2 = -8

|x+7| = 4 

=> x+7=-4 hoặc x+7=4

=> x=-11 hoặc x=-3

(x-9).(3x+6) = 0

=> x-9=0 hoặc 3x+6=0

=> x=9 hoặc x=-2

Tk mk nha

28 tháng 1 2018

1) Ta có: \(-7+x=15\)

\(\Rightarrow x=15-\left(-7\right)\)

\(\Rightarrow x=22\)

2) \(2x-10=-26\)

\(\Rightarrow2x=-26+10\)

\(\Rightarrow2x=-16\)

\(\Rightarrow x=-8\)

3) \(\left|x+7\right|=4\)

\(\Rightarrow x+7=\pm4\)

Nếu x + 7 = 4 thì x = -3

Nếu x + 7 = -4 thì x = -11

Vậy \(x=\left\{-3;-11\right\}\)

4) \(\left(x-9\right)\left(3x+6\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-9=0\\3x+6=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0+9\\3x=-6\end{cases}\Rightarrow}\orbr{\begin{cases}x=9\\x=-2\end{cases}}}\)

Vậy \(x=\left\{9;-2\right\}\)

16 tháng 2 2022

\(8x-48+4x-12-14=-x+4\)

\(\Leftrightarrow12x-75=-x+4\Leftrightarrow13x=79\Leftrightarrow x=\dfrac{79}{13}\)

\(-7\left(8-x\right)-6\left(x+9\right)=20-x\Leftrightarrow-56+7x-6x-54=20-x\)

\(\Leftrightarrow2x=130\Leftrightarrow x=65\)

\(9x-63-80+60x=-7x+15\Leftrightarrow76x=158\Leftrightarrow x=\dfrac{79}{38}\)

\(-96-16x-60+30x=-40x-16\Leftrightarrow54x=140\Leftrightarrow x=\dfrac{70}{27}\)

\(17x-102-14x-28=4x-24-2x+4\Leftrightarrow x=110\)

7 tháng 12 2017

a) X x 2 + X x 3 = 4

 X x (2 + 3) = 4

X x 5 = 4

      x = 4 : 5

      x = 0,8

b) X x 9 - X x 5 = 23

X x (9 - 5) = 23

X x 4 = 23

     X = 23 : 4

     X = 5,75

7 tháng 12 2017

a, 2x+3x=4 \(\Rightarrow\)5x=4 =>x=\(\frac{4}{5}\)

b, 9x-5x=23 => 4x=23 => x=\(\frac{23}{4}\)

24 tháng 7 2017

a) 32.x+2=1342176728

32.x=134217728-2

32.x=134217726

x=134217726:32

x=4194303,938

24 tháng 7 2017

mấy câu còn lại số lớn mik lười gõ

2:

=>x^3-1-2x^3-4x^6+4x^6+4x=6

=>-x^3+4x-7=0

=>x=-2,59

4: =>8x-24x^2+2-6x+24x^2-60x-4x+10=-50

=>-62x+12=-50

=>x=1

19 tháng 7 2023

\(l,\\ 2^x=1=2^0\\ Vậy:x=0\\ m,\\ 3^x=81=3^4\\ Vậy:x=4\\ n,\\ 3^x=37=3^3\\ Vậy:x=3\\ o,\\ 9^x=3^4=\left(3^2\right)^2=9^2\\ Vậy:x=2\)

19 tháng 7 2023

l) x = 0

m) x = 4

n) x = 3

o) x = 2

13 tháng 7 2023

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

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

\(\Rightarrow6\cdot x=6\)

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

_______________

\(43+2x=49\)

\(\Rightarrow2x=49-43\)

\(\Rightarrow2x=6\)

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

____________

\(x:2+5=11\)

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

\(\Rightarrow x:2=6\)

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

______________

\(77-11x=0\)

\(\Rightarrow11x=77\)

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

\(\Rightarrow x=7\)

_______________

\(12-4:x=8\)

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

\(\Rightarrow4:x=4\)

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

_____________

\(x:3+8=11\)

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

\(\Rightarrow x:3=3\)

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

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