Question

giup mk vs

Answer 1

\(\frac{1}{1.3}+\frac{1}{3.5}+...+\frac{1}{x\left(x+2\right)}=\frac{8}{17}\)

\(\Rightarrow\frac{1}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+...+\frac{2}{x\left(x+2\right)}\right)=\frac{8}{17}\)

\(\Rightarrow1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{x}-\frac{1}{x+2}=\frac{16}{17}\)

\(\Rightarrow1-\frac{1}{x+2}=\frac{16}{17}\)

\(\Rightarrow\frac{1}{x+2}=\frac{1}{17}\)

\(\Rightarrow x+2=17\)

\(\Rightarrow x=15\)

Vậy \(x=15\)

Answer 2

ta có:

1/1.3+1/3.5+...+1/x(x+2)=8/17

1/2.(2/1.3+2/3.5+...+2/x(x+2))=8/17

1/2.(1-1/3+1/3-1/5+...+1/x-1/x+2)=8/17

1/2.(1-1/x+2)=8/17

1-1/x+2=16/17

1/x+2=1/17

=>x=15

Answer 3

x=15

Answer 4

15

Answer 5

violympic vòng mấy đây pn??

Answer 6

x=15

Answer 7

hoc24 ko cho đăng câu hoi bằng hình nhé

Answer 8

x=15 nhé bn

Answer 9

x=15