Câu hỏi của Dung Nguyễn Thị Thùy

Question

2tính nhanh

1x3x9+2x6x18+3x9x27phần

1x5x18+2x10x36+3x15x54

Nguyễn Lê Phước Thịnh · Accepted Answer

$\frac{1\times3\times9+2\times6\times18+3\times9\times27}{1\times5\times18+2\times10\times36+3\times15\times54}$

$=\frac{1\times3\times9\times\left(1+2\times2\times2+3\times3\times3\right)}{1\times5\times18\times\left(1+2\times2\times2+3\times3\times3\right)}$

$=\frac{3\times9}{5\times18}=\frac{27}{90}=\frac{3}{10}$

Câu trả lời:

$\frac{1\times3\times9+2\times6\times18+3\times9\times27}{1\times5\times18+2\times10\times36+3\times15\times54}$

$=\frac{1\times3\times9\times\left(1+2\times2\times2+3\times3\times3\right)}{1\times5\times18\times\left(1+2\times2\times2+3\times3\times3\right)}$

$=\frac{3\times9}{5\times18}=\frac{27}{90}=\frac{3}{10}$