1+1=3 :)))

1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)=1/3

<=>1/x-1/x+1+1/x+1-1/x+2+1/x+2-1/x+3+1/x+3-1/x+4=1/3

<=>1/x-1/x+4=1/3

<=>x+4/x(x+4)-x/x(x+4) ( quy dong mau ) =1/3

<=>4/x(x+4)=1/3

<=> 4.3=x(x+4) ( nhan cheo )

<=> x(x+4)=12

<=> x^2+4x-12=0

<=>x^2-2x+6x-12=0

<=>x(x-2) + 6(x-2) =0

<=> (x-2)(x+6)=0

<=> x-2 =0 hoac x +6=0

<=>x=2 hoac x= -6

Vay x thuoc ( 2,-6 )

K mk nha !!

\(\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x\text{+}2\right)}\text{+}\frac{1}{\left(x\text{+}2\right)\left(x\text{+}3\right)}+\frac{1}{\left(x\text{+}3\right)\left(x\text{+}4\right)}=\frac{1}{3}\)

\(\Rightarrow\frac{1}{x}-\frac{1}{x\text{+}1}\text{+}\frac{1}{x\text{+}1}-\frac{1}{x\text{+}2}\text{+}.....\text{+}\frac{1}{x\text{+}3}-\frac{1}{x\text{+}4}=\frac{1}{3}\)

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

\(\Rightarrow\frac{x\text{+}4}{x\left(x\text{+}4\right)}-\frac{x}{x\left(x\text{+}4\right)}=\frac{1}{3}\)

\(\Rightarrow\frac{4}{x\left(x\text{+}4\right)}=\frac{1}{3}\)

\(\Rightarrow\frac{4}{x\left(x\text{+}4\right)}=\frac{4}{12}\)

\(\Rightarrow x\left(x\text{+}4\right)=12\)

mà x và x+4 cách nhau 4 đơn vị \(\Rightarrow x=2\)và x+4\(=\)6

Vậy \(x=2\)

\(\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+\frac{1}{\left(x+2\right)\left(x+3\right)}+\frac{1}{\left(x+3\right)\left(x+4\right)}+\frac{1}{\left(x+4\right)\left(x+5\right)}+\frac{1}{x+5}\)

\(=\frac{1}{x}-\frac{1}{x+1}+\frac{1}{x+1}-\frac{1}{x+2}+\frac{1}{x+2}-\frac{1}{x+3}+\frac{1}{x+3}-\frac{1}{x+4}+\frac{1}{x+4}-\frac{1}{x+5}+\frac{1}{x+5}\)

\(=\frac{1}{x}\)

ta có: \(\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+\frac{1}{\left(x+2\right)\left(x+3\right)}+\frac{1}{\left(x+3\right)\left(x+4\right)}+\frac{1}{\left(x+4\right)\left(x+5\right)}+\frac{1}{x+5}\)

=\(\frac{1}{x}-\frac{1}{x+1}+\frac{1}{x+1}-\frac{1}{x+2}+\frac{1}{x+2}-\frac{1}{x+3}+\frac{1}{x+3}-\frac{1}{x+4}+\frac{1}{x+4}-\frac{1}{x+5}+\frac{1}{x+5}\)

= \(\frac{1}{x}\)

Bài 1:

a) \(\frac{1}{5}x^4y^3-3x^4y^3\)

= \(\left(\frac{1}{5}-3\right)x^4y^3\)

= \(-\frac{14}{5}x^4y^3.\)

b) \(5x^2y^5-\frac{1}{4}x^2y^5\)

= \(\left(5-\frac{1}{4}\right)x^2y^5\)

= \(\frac{19}{4}x^2y^5.\)

Mình chỉ làm 2 câu thôi nhé, bạn đăng nhiều quá.

Chúc bạn học tốt!

AYUASGSHXHFSGDB HAGGAHAJF

ĐK: \(x\in R\backslash\left\{-4,-3,-2,-1\right\}\)

PT ban đầu

\(\Leftrightarrow\frac{x+2-x-1}{\left(x+1\right)\left(x+2\right)}+\frac{x+3-x-2}{\left(x+2\right)\left(x+3\right)}+\frac{x+4-x-3}{\left(x+3\right)\left(x+4\right)}+\frac{x+5-x-4}{\left(x+4\right)\left(x+5\right)}=\frac{1}{x+1}-403\\ \Leftrightarrow\frac{1}{x+1}-\frac{1}{x+2}+\frac{1}{x+2}-\frac{1}{x+3}+\frac{1}{x+3}-\frac{1}{x+4}+\frac{1}{x+4}-\frac{1}{x+5}=\frac{1}{x+1}-403\\ \Leftrightarrow\frac{1}{x+5}=403\\ \Leftrightarrow x+5=\frac{1}{403}\Leftrightarrow x=\frac{-2014}{403}\)

Chúc bạn học tốt nha.

1.

\(\frac{2x+3}{4}-\frac{5x+3}{6}=\frac{3-4x}{12}\)

\(MC:12\)

Quy đồng :

\(\Rightarrow\frac{3.\left(2x+3\right)}{12}-\left(\frac{2.\left(5x+3\right)}{12}\right)=\frac{3x-4}{12}\)

\(\frac{6x+9}{12}-\left(\frac{10x+6}{12}\right)=\frac{3x-4}{12}\)

\(\Leftrightarrow6x+9-\left(10x+6\right)=3x-4\)

\(\Leftrightarrow6x+9-3x=-4-9+16\)

\(\Leftrightarrow-7x=3\)

\(\Leftrightarrow x=\frac{-3}{7}\)

2.\(\frac{3.\left(2x+1\right)}{4}-1=\frac{15x-1}{10}\)

\(MC:20\)

Quy đồng :

\(\frac{15.\left(2x+1\right)}{20}-\frac{20}{20}=\frac{2.\left(15x-1\right)}{20}\)

\(\Leftrightarrow15\left(2x+1\right)-20=2\left(15x-1\right)\)

\(\Leftrightarrow30x+15-20=15x-2\)

\(\Leftrightarrow15x=3\)

\(\Leftrightarrow x=\frac{3}{15}=\frac{1}{5}\)

quá dễ tách ra thành 1\x-1\x+1+1\x+1-1\x+2+1\x+2-1\x+3+1\x+3-1\x+4+...+1\x+5-1\x+6

=1\x-1\x+6

=6\x(x+6)

\(\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+\frac{1}{\left(x+2\right)\left(x+3\right)}+\frac{1}{\left(x+3\right)\left(x+4\right)}+\frac{1}{\left(x+4\right)\left(x+5\right)}+\frac{1}{\left(x+5\right)\left(x+6\right)}\)\(=\frac{1}{x}-\frac{1}{x+1}+\frac{1}{x+1}-\frac{1}{x+2}+\frac{1}{x+2}-\frac{1}{x+3}+\frac{1}{x+3}-\frac{1}{x+4}+\frac{1}{x+4}-\frac{1}{x+5}+\frac{1}{x+5}-\frac{1}{x+6}\)

\(=\frac{1}{x}-\frac{1}{x+6}\)\(=\frac{6}{x\left(x+6\right)}\)

\(VT=\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+...+\frac{1}{\left(x+3\right)\left(x+4\right)}\)

\(=\frac{1}{x}-\frac{1}{x+1}+\frac{1}{x+1}-\frac{1}{x+2}+...+\frac{1}{x+3}-\frac{1}{x+4}\)

\(=\frac{1}{x}-\frac{1}{x+4}=\frac{x+4-x}{x\left(x+4\right)}=\frac{4}{x\left(x+4\right)}\)

\(\Rightarrow\frac{4}{x\left(x+4\right)}=\frac{m}{x\left(x+4\right)}=VP\Rightarrow m=4\)

Xem lại số hạng thứ 3 đúng chưa

Tự ý sửa đề; để làm theo ý mình là sao?

cái đề số hạng thứ 3 là dấu (+) không phải (.) nhé

Giai phương trình sau :

a) \(\frac{10}{\left(x+5\right)\left(x-1\right)}+\frac{3}{1-x}=\frac{5}{x+5}\)

ĐKXĐ : \(x\ne1;x\ne-5\)

Với điều kiện trên ta có :

\(\Leftrightarrow\)\(\frac{10}{\left(x+5\right)\left(x-1\right)}+\frac{-3}{x-1}=\frac{5}{x+5}\)

\(\Leftrightarrow10-3\left(x+5\right)=5\left(x-1\right)\)

\(\Leftrightarrow10-3x-15=5x-5\)

\(\Leftrightarrow-8x=0\)

\(\Leftrightarrow x=0\) (nhận)

Vậy : \(S=\left\{0\right\}\)

d) \(\frac{1}{\left(x+2\right)}+\frac{1}{\left(x+3\right)}=\frac{1}{\left(x+2\right)\left(x+3\right)}\)

ĐKXĐ : \(x\ne-2;x\ne-3\)

\(\Leftrightarrow x+3+x+2=1\)

\(\Leftrightarrow2x=-4\)

\(\Leftrightarrow x=-2\) (không nhận)

Vậy : \(S=\varnothing\)