Làm giúp e với ạ .C.ơn ac.1

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`d. 100 :` { `250 : [ 450 - ( 4 · 5^3 - 2^2 · 25 ) ]}`

`= 100 :` { `250 : [ 450 - ( 4 · 125 - 4 · 25 ) ]}`

`= 100 :` { `250 : [ 450 - ( 500 - 100 ) ]}`

`= 100 :` { `250 : [ 450 - 400 ]}`

`= 100 :` { `250 : 50 }`

`= 100 : 5`

`= 20`

Bài `17 :`

`a.`

`70 - 5 · ( x - 3 ) = 45`

`5 · ( x - 3 ) = 70 - 45`

`5 · ( x - 3 ) = 25`

`x - 3 = 25 : 5`

`x - 3 = 5`

`x = 5 + 3`

`x = 8`

`b.`

`10 + 2 · x = 4^5 : 4^3`

`10 + 2 · x = 16`

`2 · x = 16 - 10`

`2 · x = 6`

`x = 6 : 2`

`x = 3`

`c.`

`60 - 3(x-2) = 51`

`3 ( x - 2 ) = 60 - 51`

`3 ( x - 2 ) = 9`

`x - 2 = 9 : 3`

`x - 2 = 3`

`x = 3 + 2`

`x = 5`