tìm x biết 1] 3^15.(125-4:x)=3^11 2] (2.x-1).5^4=3.5^5 3] (3.x+2^4).7^3=2.7 4] (2.x+2^4).5^3=4 5] (12.x-4^3).8^3=4

`#Zkj `

`1)3^15  .(125-4:x)=3^11 `

`=>125-4:x=3^(-4) `

`=>125-4:x=1/81 `

`=>4:x=125-1/81 `

`=>4:x=10124/81 `

`=>x=81/2531 `

Vậy `x=81/2531 `

`2)(2x-1).5^4=3.5^5 `

`=>(2x-1.).625=3.3125 `

`=>(2x-1).625=9375 `

`=>2x-1=15 `

`=>2x=16 `

`=>x=8 `

Vậy `x=8 `

`3)(3x+2^4).7^3=2.7 `

`=>(3x+16).343=14 `

`=>3x+16=2/49 `

`=>3x=-782/49 `

`=>x=-782/147 `

Vậy `x=-782/147 `

`4)(2x+2^4).5^3=4 `

`=>(2x+16).125=4 `

`=>2x+16=4/125 `

`=>2x=-1996/125 `

`=>x=-998/125 `

Vậy `x=-998/125 `