Question

Tìm x biết:

\(x+\frac{4}{5.9}+\frac{4}{9.13}+\frac{4}{13.17}+...+\frac{4}{41.45}=\frac{-37}{45}\)

Answer 1

theo đề bài ta có:

\(x+\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{41}-\frac{1}{45}=\frac{-37}{45}\)

\(x+\left(\frac{1}{5}-\frac{1}{45}\right)=\frac{-37}{45}\)

\(x+\frac{8}{45}=\frac{-37}{45}\)

\(x=\frac{-37}{45}-\frac{8}{45}\)

\(x=\frac{-45}{45}=1\)

Answer 2

đặt A=4/5.9+4/9.13+4/13.17+...+4/41.45

=1/5-1/9+1/9-1/13+1/13-1/17+...+1/41-1/45

=1/5-1/45

=8/45

suy ra x+8/45=-37/45

suy ra x=-1

Answer 3

x+ 1/5.9 + ... + 1/41+ 1/45 = -37/45

x  + 1/5 - 1/9 + 1/9 -  ......+ 1/41 - 1/45 = -37/45

x+ 1/5 - 1/45 = -37 45

x+ 8/45 =-37/45

x            = -37 /45 - 8/45

x                = -1

Answer 4

x+(1/4-1/9+1/9-1/14+....+4/41-4/45)=-37/45

x+(1/4-1/45)=-37/45

x+8/45=-37/45

x=-37/45-8/45

x=29/45 

Answer 5

Trả lời,..................

X=-1

..................học tốt....................

Answer 6

\(\Leftrightarrow x+\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+\frac{1}{13}-\frac{1}{17}+...+\frac{1}{41}-\frac{1}{45}=-\frac{37}{45}\)

\(\Leftrightarrow x+\frac{1}{5}-\frac{1}{45}=-\frac{37}{45}\)

\(\Leftrightarrow x+\frac{1}{5}-\frac{1}{45}+\frac{37}{45}=0\)

\(\Leftrightarrow x+\frac{1}{5}+\frac{36}{45}=0\)

\(\Leftrightarrow x+\frac{1}{5}+\frac{4}{5}=0\)

\(\Leftrightarrow x+1=0\)

\(\Leftrightarrow x=-1\)

Answer 7

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