Question

Tìm x, biết: (12x - 4)³.8³ = 4⁶.16³

Answer 1

\(\left(12x-4\right)^3.8^3=4^{16}.16^3\)

\(\Leftrightarrow8\left(12x-4\right)^3=4^6.\left(4^2\right)^{^3}\)

\(\Leftrightarrow\left(96x-32\right)^3=4^6.4^6\)

\(\Leftrightarrow\left(96x-32\right)^3=16^6\)

\(\Leftrightarrow\left(96x-32\right)^3=\left(16^2\right)^{^3}\)

\(\Leftrightarrow\left(96x-32\right)^3=256^3\)

\(\Leftrightarrow96x-32=256\)

\(\Leftrightarrow x=\frac{256+32}{96}\)

Vậy \(x=3\)

Answer 2

(12x-4)³.8³=4³.16³

<=> [(12x-4).8]³=(4.16)³

=> (12x-4).8=4.16

<=> 12x-4=8

<=> 12x=12

=> x=1