Câu hỏi của Thao Hoang

Question

4/2.5 + 4/5.8 +...+ 4/x(x+3) = 22/35Tìm x

Trần Thanh Phương · Accepted Answer

$\frac{4}{2\cdot5}+\frac{4}{5\cdot8}+...+\frac{4}{x\cdot\left(x+3\right)}=\frac{22}{35}$$\frac{3}{2\cdot5}+\frac{3}{5\cdot8}+...+\frac{3}{x\cdot\left(x+3\right)}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{x+3}=\frac{1}{35}$$\Rightarrow x+3=35$$\Rightarrow x=32$Câu trả lời: $\frac{4}{2\cdot5}+\frac{4}{5\cdot8}+...+\frac{4}{x\cdot\left(x+3\right)}=\frac{22}{35}$$\frac{3}{2\cdot5}+\frac{3}{5\cdot8}+...+\frac{3}{x\cdot\left(x+3\right)}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{x+3}=\frac{1}{35}$$\Rightarrow x+3=35$$\Rightarrow x=32$

Dinh Thi Ngoc Mai · Answer

$\frac{4}{2\cdot5}+\frac{4}{5\cdot8}+...+\frac{4}{x\left(x+3\right)}=\frac{22}{35}$$\frac{3}{4}\left(\frac{4}{2\cdot5}+\frac{4}{5\cdot8}+...+\frac{4}{x\left(x+3\right)}\right)=\frac{3}{4}\cdot\frac{22}{35}$$\frac{3}{2\cdot5}+\frac{3}{5\cdot8}+...+\frac{3}{x\left(x+3\right)}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{x+3}=\frac{1}{35}$$\Rightarrow x+3=35$$\Rightarrow x=32$Vậy x=32Câu trả lời: $\frac{4}{2\cdot5}+\frac{4}{5\cdot8}+...+\frac{4}{x\left(x+3\right)}=\frac{22}{35}$$\frac{3}{4}\left(\frac{4}{2\cdot5}+\frac{4}{5\cdot8}+...+\frac{4}{x\left(x+3\right)}\right)=\frac{3}{4}\cdot\frac{22}{35}$$\frac{3}{2\cdot5}+\frac{3}{5\cdot8}+...+\frac{3}{x\left(x+3\right)}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{2}-\frac{1}{x+3}=\frac{33}{70}$$\frac{1}{x+3}=\frac{1}{35}$$\Rightarrow x+3=35$$\Rightarrow x=32$Vậy x=32

Lê Minh Vũ · Answer

$\frac{4}{2.5}+\frac{4}{5.8}+...+\frac{4}{x\left(x+3\right)}=\frac{22}{35}$$\Rightarrow$$\frac{3}{4}.\left(\frac{4}{2.5}+\frac{4}{5.8}+...+\frac{4}{x\left(x+3\right)}\right)=\frac{3}{4}.\frac{22}{35}$$\Rightarrow$$\frac{3}{2.5}+\frac{3}{5.8}+...+\frac{3}{x\left(x+3\right)}=\frac{33}{70}$$\Rightarrow$$\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{33}{70}$$\Rightarrow$$\frac{1}{2}-\frac{1}{x+3}=\frac{33}{70}$$\Rightarrow$$\frac{1}{x+3}=\frac{1}{2}-\frac{33}{70}$$\Rightarrow$$\frac{1}{x+3}=\frac{1}{35}$$\Rightarrow$$x+3=35$$\Rightarrow$$x=35-3$$\Rightarrow$$x=32$Câu trả lời: $\frac{4}{2.5}+\frac{4}{5.8}+...+\frac{4}{x\left(x+3\right)}=\frac{22}{35}$$\Rightarrow$$\frac{3}{4}.\left(\frac{4}{2.5}+\frac{4}{5.8}+...+\frac{4}{x\left(x+3\right)}\right)=\frac{3}{4}.\frac{22}{35}$$\Rightarrow$$\frac{3}{2.5}+\frac{3}{5.8}+...+\frac{3}{x\left(x+3\right)}=\frac{33}{70}$$\Rightarrow$$\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{33}{70}$$\Rightarrow$$\frac{1}{2}-\frac{1}{x+3}=\frac{33}{70}$$\Rightarrow$$\frac{1}{x+3}=\frac{1}{2}-\frac{33}{70}$$\Rightarrow$$\frac{1}{x+3}=\frac{1}{35}$$\Rightarrow$$x+3=35$$\Rightarrow$$x=35-3$$\Rightarrow$$x=32$

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