Đáp án + Giải thích các bước giải:
Bài `3`:
a, `6 . 9 . 8 . 6^3`
` = 6^4 . 9 . 8`
` = (2 . 3)^4 . 3^2 . 2^3`
` = 2^4 . 3^4 . 3^2 . 2^3`
` = 2^7 . 3^6`
b, `5 . 5^3 . 25`
` = 5 . 5^3 . 5^2`
` = 5^6`
c, `100 . 10^3`
` = 10^2 . 10^3`
` = 10^5`
d, `9 . 27 . 3^4`
` = 3^2 . 3^3 . 3^4`
` = 3^9`
Bài `4`:
a, `17 - x = 13`
` x = 17 - 13`
` x = 4`
Vậy `x = 4`
b, `12 + (x - 5) = 17`
` 12 + x - 5 = 17`
` 7 + x = 17`
` x = 17 - 7`
` x = 10`
Vậy `x = 10`
c, `13 + x : 3 = 25`
` x : 3 = 25 - 13`
` x : 3 = 12`
` x = 12 . 3`
` x = 36`
Vậy `x = 36`
d, `2x - 17 = 11`
` 2x = 11 + 17`
` 2x = 28`
` x = 14`
Vậy `x = 14`
e, `4x + 5x = 45`
`(4 + 5)x = 45`
` 9x = 45`
` x = 45 : 9`
` x = 5`
Vậy `x = 5`
f, `3 + 2( x - 7) = 15`
` 2(x - 7) = 15 - 3`
` 2(x - 7) = 12`
` x - 7 = 12 : 2`
` x - 7 = 6`
` x = 6 + 7`
` x = 13`
Vậy `x = 13`
g, `90 : (x + 7) = 2`
` x + 7 = 90 : 2`
` x + 7 = 45`
` x = 45 - 7`
` x = 38`
Vậy `x = 38`
h `30 : x - 5 = 10`
` 30 : x = 10 + 5`
` 30 : x = 15`
` x = 30 : 15`
` x = 2`
Vậy `x = 2`
j, `2^x = 16`
` 2^x = 2^4`
`=> x = 4`
Vậy `x = 4`
j, `14 - 2^x = 6`
` 2^x = 14 - 6`
` 2^x = 8`
` 2^x = 2^3`
`=> x = 3`
Vậy `x = 3`
Bài `5`:
`47 : XLVII`
`54 : LIV`
`98 : XCVIII`
`482 : CDLXXXII`
` 937 : CMXXXVII`
` 2153 : MMCLIII`
` 3949 : MMMCMXCIX`
