\(x\) -  4,37 = 6,37 x 1,2

\(x\)            = 7,644 + 4,37

\(x\)            = 12,014

\(3x\left(x-y\right)+x-y\)

\(=3x\left(x-y\right)+1\left(x-y\right)\)

\(=\left(x-y\right)\left(3x+1\right)\)

\(=\left(x-y\right)\left(3x+1\right)\)

Bài 2: 

a: ĐKXĐ: \(x\notin\left\{1;-1\right\}\)

\(P=\dfrac{x}{3\left(x-1\right)}-\dfrac{x^2-1}{3\left(x-1\right)\left(x+1\right)}\)

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

b: Để P=2 thì 3x-3=1/2

=>3x=7/2

=>x=7/6

c: Vì x=1 không thỏa mãn ĐKXĐ nên khi x=1 thì P không có giá trị

Bài này quá dễ 

x/40 - x/50= 1/3

<=>5x/200 - 4x/200=1/3

<=> x/200= 1/3

<=> x= 200/3.

bạn ê, mik bị ngu toán, lười suy nghĩ ấy mà nên đừng nói dễ hay khó j vs mik

Ờm, k cho mình đi

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

\(ĐK:x\le\dfrac{3}{2}\)

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

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\0=0\left(đúng\right)\end{matrix}\right.\)

Vậy \(S=\left\{x\in R;x=\dfrac{3}{2}\right\}\)

a.\(5x^2-4x-1=0\)

\(\Delta=\left(-4\right)^2-4.5.\left(-1\right)=16+20=36>0\)

=> pt có 2 nghiệm phân biệt

\(\left\{{}\begin{matrix}x_1=\dfrac{4+\sqrt{36}}{10}=1\\x_2=\dfrac{4-\sqrt{36}}{10}=-\dfrac{1}{5}\end{matrix}\right.\)

b.\(7x^2-2\sqrt{7}x+1=0\)

\(\Delta=\left(-2\sqrt{7}\right)^2-4.1.7\)

    \(=28-28=0\)

=> pt có nghiệm kép

\(x_1=x_2=\dfrac{2\sqrt{7}}{2.7}=\dfrac{\sqrt{7}}{7}\)

a, \(\Delta=\left(-4\right)^2-4.5.\left(-1\right)=16+20=36>0\)

\(x_1=\dfrac{4+6}{10}=1\\ x_2=\dfrac{4-6}{10}=\dfrac{-1}{5}\)

\(b,\Delta=\left(-2\sqrt{7}\right)^2-4.7.1=28-28=0\)

\(\Rightarrow\) pt có nghiệm kép là: \(\dfrac{2\sqrt{7}}{14}=\dfrac{\sqrt{7}}{7}\)

\(c,4x^2-2=0\\ \Leftrightarrow2x^2-1=0\\ \Leftrightarrow x^2=\dfrac{1}{2}\\ \Leftrightarrow x=\pm\dfrac{\sqrt{2}}{2}\)

\(d,\left\{{}\begin{matrix}4x+y=3\\2x-3y=8\end{matrix}\right.\\ \Leftrightarrow \left\{{}\begin{matrix}y=3-4x\\2x-3\left(3-4x\right)=8\end{matrix}\right.\\\Leftrightarrow\left\{{}\begin{matrix}y=3-4x\\2x-9+12x=8\end{matrix}\right.\Leftrightarrow\\ \left\{{}\begin{matrix}y=3-4x\\14x=17\end{matrix}\right.\Leftrightarrow\\ \left\{{}\begin{matrix}y=3-4.\dfrac{17}{14}\\x=\dfrac{17}{14}\end{matrix}\right.\Leftrightarrow\\ \left\{{}\begin{matrix}y=-\dfrac{13}{7}\\x=\dfrac{17}{14}\end{matrix}\right.\)

X = 1 hoặc X = -1

|x|=7 suy ra x=7 hoặc x=-7