Đáp án + Giải thích các bước giải:
`a)` `70 : (x - 3) = (3^4 - 1) : 4 - 10`
`70 : (x - 3) = (81 - 1) : 4 - 10`
`70 : (x - 3) = 80 : 4 - 10`
`70 : (x - 3) = 20 - 10`
`70 : (x - 3) = 10`
`x - 3 = 70 : 10`
`x - 3 = 7`
`x = 7 + 3`
`x = 10`
`b)` `75 : (x + 2) = 5^3 - (3^2 + 4^2) . 2^2`
`75 : (x + 2) = 125 - (9 + 16) . 4`
`75 : (x + 2) = 125 - 25 . 4`
`75 : (x + 2) = 125 - 100`
` 75 : (x + 2) = 25`
`x + 2 = 75 : 25`
`x + 2 = 3`
`x = 3 - 2`
`x = 1`
`c)` `260 : (x + 4) = 5. (2^3 + 5) - 3. (3^2 + 2^2)`
`260 : (x + 4) = 5. (8 + 5) - 3. (9 + 4)`
`260 : (x + 4) = 5. 13 - 3. 13`
`260 : (x + 4) = 13. (5 - 3)`
`260 : (x + 4) = 13 . 2`
`260 : (x + 4) = 26`
`x + 4 = 260 : 26`
`x + 4 = 10`
`x = 10 - 4`
`x = 6`
`d)` `(2^2 + 3). (x - 5) + 14 = 5^2 + 124 : 2^2`
`(4 + 3). (x - 5) + 14 = 25 + 124 : 4`
`7 . (x - 5) + 14 = 25 + 31`
`7. (x - 5) + 14 = 56`
`7. (x - 5) = 56 - 14`
`7. (x - 5) = 42`
`x - 5 = 42 : 7`
`x - 5 = 6`
`x = 6 + 5`
`x = 11`
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