Đáp án+Giải thích các bước giải:
Bài `8:`
`a) (5^5)/(5^x) = 5^(18)`
`=> 5^(5-x) = 5^(18)`
`=> 5 - x = 18`
`=> x = -13`
Vậy `x = -13`
`b) (2^(4-x))/(16^5) = 32^6`
`=> (2^(4-x))/(2^(20)) = 2^(30)`
`=> 2^(4-x - 20) = 2^(30)`
`=>-x - 16 = 30`
`=> -x = 46`
`=> x = -46`
Vậy `x = -46`
`c) (2^(2x-3))/(4^(10)) = 8^3 . 16^5`
`=> (2^(2x-3))/((2^2)^(10)) = (2^3)^3 . (2^4)^5`
`=> (2^(2x-3))/(2^(20)) = 2^9 . 2^(20)`
`=> 2^(2x-3 - 20) = 2^29`
`=> 2x - 23 = 29`
`=> 2x = 52`
`=> x = 26`
Vậy `x = 26`
`d) (2^3)/(2^x) = 4^5`
`=> 2^(3-x)= 2^ (10)`
`=> 3-x = 10`
`<=> x = -7`
Vậy `x = -7`
`e) 9. 5^x = 6. 5^6 + 3. 5^6`
`=> 9. 5^x = (6+3).5^6`
`=> 9. 5^x = 9.5^6`
`=> 5^x = 5^6`
`=> x =6`
Vậy `x = 6`
`f) 7 . 2^x = 2^9 + 5.2^8`
`=> 7 . 2^x = 2.2^8 + 5.2^8`
`=> 7 . 2^x = 7 . 2^8`
`=> 2^x = 2^8`
`=> x = 8`
Vậy `x = 8`
