b) \(27x^3-54x^2+36x=8\)

\(\Rightarrow27x^3-54x^2+36x-8=0\)

\(\Rightarrow\left(3x\right)^3-3.\left(3x\right)^2.2+3.3x.2^2-2^3=0\)

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

\(\Rightarrow3x-2=0\)

\(\Rightarrow3x=2\)

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

(2x-5)^2-(5+2x)^2=0
<=>(2x-5-5-2x)(2x-5+5+2x)=0
<=>(-10).(4x)=0
<=>(-40x)=0
<=>x =0
27x^3-54x^2+36x=8
<=>27x^3-54x^2+36x-8=0
<=>(3x-2)^3=0
<=>3x-2=0
<=>3x=2
<=>x=2/3

a,\(\left(2x-5\right)^2-\left(5+2x\right)^2=0\)

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

Do \(\left(2x-5\right)^2\ge0\)

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

\(\Rightarrow2x-5=0\)

\(\Rightarrow x=\dfrac{5}{2}\)

@Yukru giúp câu b với!

\(6x^2-9xy+10x-15y\\ =3x\left(2x-3y\right)+5\left(2x-3y\right)\\ =\left(3x+5\right)\left(2x-3y\right)\\ 27x^3+36x^2y+12xy^2\\ =3x\left(9x^2+12xy+4y^2\right)\\ =3x\left(3x+2y\right)^2\)

a) \(6x^2-9xy+10x-15y=\left(6x^2-9xy\right)+\left(10x-15y\right)\)

                                          \(=3x\left(2x-3y\right)+5\left(2x-3y\right)\)

                                          \(=\left(3x+5\right)\left(2x-3y\right)\)

b) \(27x^3+36x^2y+12xy^2=3x\left(9x^2+12xy+4y^2\right)\)

                                        \(=3x\left[\left(3x\right)^2+2\cdot3x\cdot2y+\left(2y\right)^2\right]\)

                                        \(=3x\left(3x+2y\right)^2\)

                                   \(\)

Đề ko có vấn đề chứ ạ ? 

\(27x^2.x+69x^2+36x=0\)

Tương đương vs pt : \(\Leftrightarrow27x^3+69x^2+36x=0\)

\(\Leftrightarrow3x\left(9x^2+23x+12\right)=0\)

TH1 : \(3x=0\Leftrightarrow x=0\)

TH2 : \(\Delta=23^2-4.12.9=529-432=97>0\)

Phương trình có 2 nghiệm phân biệt

\(x_1=\frac{-23-\sqrt{97}}{3};x_2=\frac{-23+\sqrt{97}}{3}\)

\(a,\Rightarrow4x\left(x^2-9\right)=0\\ \Rightarrow4x\left(x-3\right)\left(x+3\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\\ b,\Rightarrow\left(3x-5-x-1\right)\left(3x-5+x+1\right)=0\\ \Rightarrow\left(2x-6\right)\left(4x-4\right)=0\\ \Rightarrow2\left(x-3\right)4\left(x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

a) \(\Rightarrow4x\left(x^2-9\right)=0\)

\(\Rightarrow4x\left(x-3\right)\left(x+3\right)=0\)

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

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

\(\Rightarrow\left(2x-6\right)\left(4x-4\right)=0\)

\(\Rightarrow8\left(x-3\right)\left(x-1\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\)

tìm x nha

+(x-3)²-x²=11

x²-6x+9-x²=11

-6x+9=11

-6x=2

x=2:-6

x=-1/3

(6x-3)²-36x(x-1)=40

36x²-36x+9-36x²+36x=40

9=40

=> đề sai

(2-x)²-7(x²+11)=0

4-4x+x²-7x²-77=0

-73-4x-6x²

ht bt 

\(8-36x+54x^2-27x^3=0\)

\(=2^3-3.2^2.3x+3.9x^2.2-3x^3\)

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

\(\Rightarrow2-3x=0\Rightarrow x=\frac{2}{3}\)

\(\text{1) -5x - (-3)= 13}\)

\(\Rightarrow-5x=10\)

\(x=10:-5\)

\(x=-2\)

\(\text{2) |x-3| - 7= 13}\)

\(\Rightarrow|x-3|=20\)

\(\Rightarrow\orbr{\begin{cases}x-3=20\\x-3=-20\end{cases}\Leftrightarrow\orbr{\begin{cases}x=23\\x=-17\end{cases}}}\)

\(\text{3) 17- (43 - |x|)= 45}\)

\(\Rightarrow43-|x|=-28\)

\(|x|=71\)

\(\Rightarrow\orbr{\begin{cases}x=71\\x=-71\end{cases}}\)

\(\text{5) (x-2).(x+15)= 0}\)

\(\Rightarrow\orbr{\begin{cases}x-2=0\\x+15=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-15\end{cases}}}\)

4,\(\text{4) (x-3).(x-5) < 0}\)\(\left(x-3\right).\left(x-5\right)< 0\)

\(\Rightarrow\left(x-3\right)\)và \(\left(x-5\right)\)trái dấu

Mà \(\left(x-3\right)>\left(x-5\right)\Rightarrow\left(x-3\right)>0\)và \(\left(x-5\right)< 0\)

\(+,x-3>0\Rightarrow x>3\)

\(+,x-5< 0\Rightarrow x< 5\)

\(\Rightarrow3< x< 5\)

\(\)Mà \(x\in Z\)

\(\Rightarrow x=4\)

học tốt

1<=>-5x+3=13

<=>-5x=10

<=>x=-2

2<=>|x-3|=20

th1:x-3=20

<=>x=23

th2:x-3=-20

<=>x=-17

3,<=>17-43+|x|=45

<=>|x|=71

th1:x=71

th2:x=-71

4<=>x-3<0                  x-5>0

<=>x<3                       x>5(loại vì ko có số naod vừa lớn hơn 5 và nhỏ hơn 3)

<=>x-3>0                   x-5<0

<=>x>3                      x<5

=>3<x<5

5,<=>x-2=0                  x+15=0

<=>x=2                       x=-15

https://www.youtube.com/channel/UCb2H-q6FmW61PgcsL1OGPfw ủng hộ bạn t:))

1) -5x- (-3)= 13

=>-5x +3= 13   => -5x = 10  => x = 10: (-5)   => x =-2

2) |x-3|- 7=  13

=>|x-3|= 20  =>  \(\orbr{\begin{cases}x-3=20\\x-3=-20\end{cases}}\Rightarrow\orbr{\begin{cases}x=20+3\\x=3-20\end{cases}}\Rightarrow\orbr{\begin{cases}x=23\\x=-17\end{cases}}\)

4)

 \(17-\left(43-\left|x\right|\right)=45\\ \Rightarrow43-\left|x\right|=-28\Rightarrow\left|x\right|=71\Rightarrow\orbr{\begin{cases}x=71\\x=-71\end{cases}}\)

5)\(\left(x-2\right).\left(x+15\right)=0\Rightarrow\orbr{\begin{cases}x-2=0\\x+15=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=2\\x=-15\end{cases}}\)