\(x=\dfrac{76}{57}\times36=48\)

\(\dfrac{x}{36}=\dfrac{76}{57}\)

\(\dfrac{x}{36}=\dfrac{4}{3}\)

\(\dfrac{x}{36}=\dfrac{48}{36}\)

\(\Rightarrow x=48\)

x=48

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q, ed,x

x : 36 = \(\dfrac{76}{57}\)

x = \(\dfrac{76}{57}\)x 36

x = 48

tick mik nha 

X/36 = 76/57

=> X = 36x76/57

=> X = 48

x ko tồn tại

48/36

\(\dfrac{1}{1.4}+\dfrac{1}{4.7}+\dfrac{1}{7.10}+...+\dfrac{1}{x\left(x+3\right)}=\dfrac{125}{376}\)

\(\Leftrightarrow\dfrac{1}{3}\left(1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+...+\dfrac{1}{x}-\dfrac{1}{x+3}\right)=\dfrac{125}{376}\)

\(\Leftrightarrow\dfrac{1}{3}\left(1-\dfrac{1}{x+3}\right)=\dfrac{125}{376}\left(x\ne0;x\ne-3\right)\)

\(\Leftrightarrow\dfrac{x+3-1}{x+3}=\dfrac{3.125}{376}\Leftrightarrow\dfrac{x+2}{x+3}=\dfrac{3.125.}{376}.\dfrac{\left(x+3\right)}{x+3}\)

\(\Leftrightarrow376\left(x+2\right)=3.125.\left(x+3\right)\)

\(\Leftrightarrow376x+752=375x+1125\)

\(\Leftrightarrow376x-375x=1125-752\Leftrightarrow x=373\left(x\in N^{\cdot}\right)\)

`3x-15/(5*8)-15/(8*11)-15/(11*14)-...-15/(47*50)=2 1/10`

`3x-(15/(5*8)+15/(8*11)+15/(11*14)+...+15/(47*50))=21/10`

`3x-5(3/(5*8)+3/(8*11)+3/(11*14)+...+3/(47*50))=21/10`

`3x-5(1/5-1/8+1/8-1/11+1/11-1/14+...+1/47-1/50)=21/10`

`3x-5(1/5-1/50)=21/10`

`3x-5*9/50=21/10`

`3x-9/10=21/10`

`3x=21/10+9/10`

`3x=3`

`x=1`

\(\left|2x-3\right|-x=\left|2-x\right|\)

TH1 \(\left\{{}\begin{matrix}2x-3\ge0\\2-x\ge0\end{matrix}\right.\Leftrightarrow\dfrac{3}{2}\le x\le2\)

\(\Leftrightarrow2x-3-x=2-x\Leftrightarrow x=\dfrac{5}{2}\left(l\right)\)

TH2 \(\left\{{}\begin{matrix}2x-3\ge0\\2-x\le0\end{matrix}\right.\Leftrightarrow x\ge2\)

\(\Leftrightarrow2x-3-x=x-2\Leftrightarrow0=1\left(vl\right)\)

Th3 \(\left\{{}\begin{matrix}2x-3\le0\\2-x\ge0\end{matrix}\right.\Leftrightarrow x\le\dfrac{3}{2}\)

\(\Leftrightarrow3-2x-x=x-2\Leftrightarrow x=\dfrac{5}{4}\left(nhận\right)\)

TH4 \(\left\{{}\begin{matrix}2x-3\le0\\2-x\le0\end{matrix}\right.\left(vl\right)\)

vậy \(S=\left\{\dfrac{5}{4}\right\}\)

\(\left(2x+1\right)\left(x^2-x\right)+x\left(5+x-2x^2\right)=3x+7\)

\(2x^3-2x^2+x^2-x+5x+x^2-2x^3=3x+7\)

\(5x-x=3x+7\)

\(4x-3x=7\)

\(x=7\)

(2x+1)(x^2-x)+x(-2x^2+x+5)=3x+7

=>2x^3-2x^2+x^2-x-2x^3+x^2+5x=3x+7

=>-x^2-x+x^2+5x=3x+7

=>4x=3x+7

=>x=7