\(a,2x\left(x^3-3\right)-2x^4=18\\ 2x^4-6x-2x^4=18\\ -6x=18\\ x=-3\)

\(b,9x\left(4-x\right)+\left(3x+1\right)^2=2\\ 36x-9x^2+9x^2+6x+1=2\\ 42x=2-1\\ 42x=1\\ x=\dfrac{1}{42}\)

\(a,\Leftrightarrow2x^4-3x-2x^4=18\Leftrightarrow-3x=18\Leftrightarrow x=-6\\ b,\Leftrightarrow36x-9x^2+9x^2+6x+1=2\\ \Leftrightarrow42x=1\Leftrightarrow x=\dfrac{1}{42}\)

\(\left|x-\dfrac{1}{2}\right|\left|2x-\dfrac{3}{4}\right|=2x-\dfrac{3}{4}\)

\(\left\{{}\begin{matrix}\left|x-\dfrac{1}{2}\right|\ge0\\\left|2x-\dfrac{3}{4}\right|\ge0\end{matrix}\right.\)

\(\Rightarrow2x-\dfrac{3}{4}\ge0\)

\(\Rightarrow\left|2x-\dfrac{3}{4}\right|=2x-\dfrac{3}{4}\)

\(\Rightarrow\left|x-\dfrac{1}{2}\right|=1\)

\(\Rightarrow\left[{}\begin{matrix}x-\dfrac{1}{2}=1\Rightarrow x=\dfrac{3}{2}\\x-\dfrac{1}{2}=-1\Rightarrow x=-\dfrac{1}{2}\end{matrix}\right.\)

\(2x-\dfrac{3}{4}\ge0\Rightarrow2x\ge\dfrac{3}{4}\Rightarrow x\ge\dfrac{3}{2}\)

Vậy xảy ra khi:

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

mk giải cho bạn ở trên r đó

câu trên mk làm rồi

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

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

\(\Rightarrow2x^2-x-2x+1=2x^2-6x+3x-9\)

\(\Rightarrow-x-2x+6x-3x=-1-9\)

\(\Rightarrow0=-10\) (vô lí)

Vậy ko tồn tại giá trị của x.

2(x-1)-3(2x+2)-4(2x+3)=16

2x-2-6x+6-8x+12=16

(2x-6x-8x)-(2+6+12)=16

(-12).x-20=16

(-12).x=16+20=36

x=36:(-12)=-3

2(x-1)-3(2x+2)-4(2x+3)=16

2x-2-6x-6-8x-12=16

2x-6x-8x=16+2+6+12

-12x=36

x=-3

Bạn ấy trả lời đúng rồi

Mike bạn ấy nhé

Chúc học tốt

\(\dfrac{x}{x+2}+\dfrac{2}{x-2}+\dfrac{2x+4}{4-x^2}\\ =\dfrac{x\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}+\dfrac{2\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}-\dfrac{2x+4}{\left(x-2\right)\left(x+2\right)}\)

\(=\dfrac{x^2-2x+2x+4-2x-4}{\left(x-2\right)\left(x+2\right)}\)

\(=\dfrac{x^2-2x}{\left(x-2\right)\left(x+2\right)}\\ =\dfrac{x\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}\\ =\dfrac{x}{x+2}\)

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

với x=-4 thì

\(\dfrac{-4}{-4+2}=\dfrac{-4}{-2}=2\)

\(=>P=\dfrac{x}{x+2}+\dfrac{2}{x-2}+\dfrac{-2x-4}{x^2-4}\)`(x ne +-2)`

\(P=\dfrac{x\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}+\dfrac{2\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}+\dfrac{-2x-4}{\left(x+2\right)\left(x-2\right)}\)

\(P=\dfrac{x^2-2x+2x+4-2x-4}{\left(x+2\right)\left(x-2\right)}=\dfrac{x^2-2x}{\left(x-2\right)\left(x+2\right)}=\dfrac{x\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}\)

\(P=\dfrac{x}{x+2}\)

`|x+1| =3`

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

`=> [(x=3-1=2(ktm) ),(x=-3-1=-4(t/m)):}`

Thay `x=-4` vào `P` ta đc

`P= (-4)/(-4+2) = 2`

nhan tung ve ra roi triet tieu 

làm bừa thui,ai tích mình mình tích lại

Số số hạng là : 

Có số cặp là :

50 : 2 = 25 ( cặp )

Mỗi cặp có giá trị là :

99 - 97 = 2 

Tổng dãy trên là :

25 x 2 = 50

Đáp số : 50

=50

..............học tốt...............