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Question

Tính nhanh:2/1x2x3+2/2x3x4+2/3x4x5+2/4x5x6+2/5x6x7+2/6x7x8Giúp mình với!Thanks

soyeon_Tiểu bàng giải · Accepted Answer

$\frac{2}{1.2.3}+\frac{2}{2.3.4}+...+\frac{2}{6.7.8}$$=\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{6.7}-\frac{1}{7.8}$$=\frac{1}{1.2}-\frac{1}{7.8}$$=\frac{1}{2}-\frac{1}{56}$$=\frac{28}{56}-\frac{1}{56}=\frac{27}{56}$Dấu . là nhân nhaCâu trả lời: $\frac{2}{1.2.3}+\frac{2}{2.3.4}+...+\frac{2}{6.7.8}$$=\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{6.7}-\frac{1}{7.8}$$=\frac{1}{1.2}-\frac{1}{7.8}$$=\frac{1}{2}-\frac{1}{56}$$=\frac{28}{56}-\frac{1}{56}=\frac{27}{56}$Dấu . là nhân nha

Nguyễn Nhật Minh · Answer

$\frac{2}{1.2.3}=\frac{1}{1.2}-\frac{1}{2.3}$$\frac{2}{2.3.4}=\frac{1}{2.3}-\frac{1}{3.4}$.......................................$\frac{2}{6.7.8}=\frac{1}{6.7}-\frac{1}{7.8}$S= $\frac{1}{1.2}-\frac{1}{7.8}=\frac{27}{56}$Câu trả lời: $\frac{2}{1.2.3}=\frac{1}{1.2}-\frac{1}{2.3}$$\frac{2}{2.3.4}=\frac{1}{2.3}-\frac{1}{3.4}$.......................................$\frac{2}{6.7.8}=\frac{1}{6.7}-\frac{1}{7.8}$S= $\frac{1}{1.2}-\frac{1}{7.8}=\frac{27}{56}$

Edogawa Conan · Answer

$\frac{2}{1.2.3}+\frac{2}{2.3.4}+...+\frac{2}{6.7.8}$$=\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{6.7}-\frac{1}{7.8}$$=\frac{1}{1.2}-\frac{1}{7.8}$$=\frac{1}{2}-\frac{1}{56}$$=\frac{28}{56}-\frac{1}{56}=\frac{27}{56}$Câu trả lời: $\frac{2}{1.2.3}+\frac{2}{2.3.4}+...+\frac{2}{6.7.8}$$=\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{6.7}-\frac{1}{7.8}$$=\frac{1}{1.2}-\frac{1}{7.8}$$=\frac{1}{2}-\frac{1}{56}$$=\frac{28}{56}-\frac{1}{56}=\frac{27}{56}$

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