bạn mạnh sai dùi

Rút gọn hết ta được :

a/ 41x - 17 = -21

=> 41x = -4 => x = 4/41

b/ 34x - 17 = 0 

=> 34x = 17

=> x = 17/34 = 1/2

c/ 19x + 56 = 52 

=> 19x = -4

=> x = -4/19

d/ 20x² - 16x - 34 = 10x² + 3x - 34

=> 10x² - 19x = 0

=> x(10x - 19) = 0

=> x = 0 

hoặc 10x - 19 = 0 => 10x = 19 => x = 19/10

Vậy x = 0 ; x = 19/10

Rút gọn hết ta được :

a/ 41x - 17 = -21

=> 41x = -4 => x = 4/41

b/ 34x - 17 = 0

=> 34x = 17

=> x = 17/34 = 1/2

c/ 19x + 56 = 52

=> 19x = -4

=> x = -4/19

d/ 20x 2 - 16x - 34 = 10x 2 + 3x - 34

=> 10x 2 - 19x = 0

=> x(10x - 19) = 0

=> x = 0 hoặc 10x - 19 = 0

=> 10x = 19

=> x = 19/10

Vậy x = 0 ; x = 19/10 

tìm y nữa 

mình viết thiếu

`a,x^2+2x+1=9`

`<=>x^2+2.x.1+1^2=9`

`<=>(x+1)^2=3^2`

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

\(\Leftrightarrow\left[{}\begin{matrix}x+1=3\\x+1=-3\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=-4\end{matrix}\right.\)

`b, x^2-4x-21=0`

`<=>x^2+3x-7x-21=0`

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

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

\(\Leftrightarrow\left[{}\begin{matrix}x+3=0\\x-7=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-3\\x=7\end{matrix}\right.\)

`c,x^2+10x-24=0`

`<=>x^2+12x-2x-24=0`

`<=>x(x+12)-2(x+12)=0`

`<=>(x+12)(x-2)=0`

\(\Leftrightarrow\left[{}\begin{matrix}x+12=0\\x-2=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-12\\x=2\end{matrix}\right.\)

a: =>(x+1)^2=9

=>(x+1+3)(x+1-3)=0

=>(x+4)(x-2)=0

=>x=2 hoặc x=-4

b: =>x^2-7x+3x-21=0

=>(x-7)(x+3)=0

=>x=7;x=-3

c: =>x^2+12x-2x-24=0

=>(x+12)(x-2)=0

=>x=2 hoặc x=-12

Bài 1:

a) \(9\left(4x+3\right)^2=16\left(3x-5\right)^2\)

\(114x^2+216x+81=114x^2-480x+400\)

\(144x^2+216x=144x^2-480x+400-81\)

\(114x^2+216=114x^2-480x+319\)

\(696x=319\)

\(\Rightarrow x=\frac{11}{24}\)

b) \(\left(x^3-x^2\right)^2-4x^2+8x-4=0\)

\(\left(x-1\right)^2\left(x^2+2\right)\left(x+\sqrt{2}\right)\left(x-\sqrt{2}\right)=0\)

\(\Rightarrow x=1\)

c) \(x^5+x^4+x^3+x^2+x+1=0\)

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

\(\Rightarrow x=-1\)

Bài 2:

a) \(5x^3-7x^2-15x+21=0\)

\(\left(5x-7\right)\left(x+\sqrt{3}\right)\left(x-\sqrt{3}\right)=0\)

\(\Rightarrow x=\frac{7}{5}\)

b) \(\left(x-3\right)^2=4x^2-20x+25\)

\(x^2-6x+9-25=4x^2-20x+25\)

\(x^2-6x+9=4x^2-20x+25-25\)

\(x^2-6x-16=4x^2-20x\)

\(x^2+14x-16=4x^2-4x^2\)

\(-3x^2+14x-16=0\)

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

c) \(\left(x-1\right)^2-5=\left(x+2\right)\left(x-2\right)-x\left(x-1\right)\)

\(x^2-2x=x-4\)

\(x^2-2x=x-4+4\)

\(x^2-2x=x-x\)

\(x^2-3x=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=3\end{cases}}\)

d) \(\left(2x-3\right)^3-\left(2x+3\right)\left(4x^2-1\right)=-24\)

\(-48x^2+56x-24=-24\)

\(-48x^2+56x=-24+24\)

\(-48x^2+56=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=\frac{7}{6}\end{cases}}\)

mình ko chắc

Bài 1

A, 11/24

B, -1

chúc bn học tốt

a, (x + 2)(x² - 2x + 4 ) - x(x + 3)(x - 3) = 26

<=> x³ + 8 - x(x² - 9) = 26

<=> x³ + 8 - x³ + 9x = 26

<=> 9x - 18 = 0

<=> 9x = 18

<=> x = 2
b, (x - 3)(x² + 3x + 9) - x(x - 4)(x + 4) = 21

<=> x³ - 27 - x(x² - 16) = 21

<=> x³ - 27 - x³ + 16x = 21

<=> 16x - 48 = 0

<=> 16x = 48

<=> x = 3
c, (2x - 1)(4x² + 2x + 1) - 4x(2x² - 3) = 23

<=> 8x³ - 1 - 8x³ + 12x = 23

<=> 12x - 24 = 0

<=> 12x = 24

<=> x = 2

a/\(\left(x+2\right)\left(x^2-2x+4\right)-x\left(x+3\right)\left(x-3\right)=26\)

↔ \(x^3+2^3\)\(-x\left(x^2-3^2\right)\)= 26

↔\(x^3+8-x^3+9x=26\)

↔\(9x=18\leftrightarrow x=2\)

Vậy x=2

b/\(\left(x-3\right)\left(x^2+3x+9\right)-x\left(x-4\right)\left(x+4\right)=21\)

\(\Leftrightarrow x^3-3^3-x\left(x^2-4^2\right)=21\)

\(\Leftrightarrow x^3-9-x^3+16x=21\)

\(\Leftrightarrow16x=30\)

\(\Leftrightarrow x=\frac{15}{8}\)

Vậy \(x=\frac{15}{8}\)

c/\(\left(2x-1\right)\left(4x^2+2x+1\right)-4x\left(2x^2-3\right)=23\)

↔\(\left(2x\right)^3-1^3-4x\left(2x^2-3\right)=23\)

↔\(8x^3-1-8x^3+12x=23\)

↔\(12x=24\leftrightarrow x=2\)

Vậy x=2

Ta có 3(2x - 1) - 12 = 21

=> 3(2x - 1) - 33 = 0

=> 3(2x - 1 - 11) = 0

=> 2x - 12 = 0 

=> 2x = 12

=> x = 6 

3. ( 2x - 1 ) - 12 = 21

  3 . ( 2x - 1 )     = 21 + 12

    3 . ( 2x - 1 )   = 33

           2x - 1     = 33 : 3

           2x - 1     = 11

              2x        = 11 + 1

               2x       = 12

                 x        = 12 : 2

                x         = 6

Vậy x = 6