Đáp án + Giải thích các bước giải:
Bài `1`: Tính
`C = (2^30 . 5^7 + 2^13 . 5^27)/(2^27 . 5^7 + 2^10 . 5^27)`
` = ( 5^7 . 2^13 . (2^17 + 5^20) )/( 5^7 . 2^10 . (2^17 + 5^20) )`
` = 2^3 `
` C = 8`
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`D = (3/7)^5 . (7/3)^(-1) . (5/3)^6 : (343/625)^(-2)`
` = (3/7)^5 . (3/7) . (5/3)^6 . (343/625)^2`
` = (3/7)^6 . (5/3)^6 . ((7^3)/(5^4) )^2`
` = (3/7 . 5/3)^6 . (7^6)/(5^8)`
` = (5/7)^6 . (7^6)/(5^8)`
` = (5^6)/(7^6) . (7^6)/(5^8)`
` D = `1/(5^2) = 1/25`