=>x+3/2x-3/4=5/6

=>5/2x=19/12

=>x=19/30

tk ủng hộ nha mọi người

x = 4

Tk mình nha!!!>.<

\(P=\frac{x+1}{x-3}=\frac{x-3+4}{x-3}=1+\frac{4}{x-3}\)

\(P\in Z\Rightarrow4⋮x-3\Leftrightarrow x-3\inƯ_4=\left(1;-1;2;-2;4;-4\right)\)

a) \(3x+2\left(5-x\right)=-11\)

\(\Leftrightarrow3x+10-2x=-11\)

\(\Leftrightarrow x=-21\)

b) \(3x^2-3x\left(x-2\right)=36\)

\(\Leftrightarrow3x^2-3x^2+6x=36\)

\(\Rightarrow x=6\)

?????????????????????????????????????

3x + 2( 5 - x ) = -11

<=> 3x + 10 - 2x = -11

<=> x + 10 = -11

<=> x = -21

3x² - 3x( x - 2 ) = 36

<=> 3x² - 3x² + 6x = 36

<=> 6x = 36

<=> x = 6

=>2/2.3+2/3.4+2/4.5+............+2/x.(x+1)=2007/2019

=>2(1/2.3+1/3.4+1/4.5+.......+1/(x+1))=2007/2019

=>2(1/2-1/3+1/3-1/4+1/4-1/5+.....+1/x-1/x+1)=2007/2019

=>2(1/2-1/2x+1)=2007/2019

=>1-2/x+1=2007/2009=>2/x+1=1-2007/2019=12/2019

=>x+1=336,5.Vay x=335,5

\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\left(x+1\right)}\)\(=\frac{2007}{2019}\)

\(\frac{2}{6}+\frac{2}{12}+\frac{2}{20}+...+\frac{2}{x\left(x+1\right)}=\frac{2007}{2019}\)

\(2\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{x.\left(x+1\right)}\right)\)\(=\frac{2007}{2019}\)

\(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+1}\)\(=\frac{2007}{2019}\div2\)

\(\frac{1}{2}-\frac{1}{x+1}=\frac{669}{1346}\)

\(\frac{1}{x+1}=\frac{1}{2}-\frac{669}{1346}\)

\(\frac{1}{x+1}=\frac{2}{673}\)

\(\frac{2}{\left(x+1\right)2}=\frac{2}{673}\)

\(\Rightarrow\left(x+1\right)2=673\)

\(\Rightarrow x+1=673\div2\Rightarrow x+1=336,5\Rightarrow x=336,5-1=335,5\)

Để pt có 2 nghiệm dương:

\(\left\{{}\begin{matrix}\Delta'=\left(m-3\right)^2-\left(m-1\right)\ge0\\x_1+x_2=-2\left(m-3\right)>0\\x_1x_2=m-1>0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}m^2-7m+10\ge0\\m< 3\\m>1\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\left[{}\begin{matrix}m\ge5\\m\le2\end{matrix}\right.\\m< 3\\m>1\end{matrix}\right.\)

\(\Rightarrow1< m\le2\)

ĐKXĐ: x khác 0; x khác 2

x+3/x=3x-1/3(x-2)

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

<=>3x^2 + 3x - 6 = 3x^2 - x

<=>4x=6

<=>x=3/2(tm ĐKXĐ)

vậy,..........

\(\left\{{}\begin{matrix}x.y=100\\\left(x-1\right)\left(y+5\right)=100\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=100:x\\\left(x-1\right)\left(\left(100:x\right)+5\right)\end{matrix}\right.\)\(\Leftrightarrow\left\{{}\begin{matrix}x=5\\y=20\end{matrix}\right.\)

N⁰ (x;y) của hệ là:(5;20)