Đáp án:
Giải thích các bước giải:
a) `(2x+1)^3=343`
`⇔ (2x+1)^3=7^3`
`⇔ 2x+1=7`
`⇔ 2x=8`
`⇔ x=4`
Vậy `x=4`
b) `(x-2)^4=81`
`⇔ (x-2)^4=3^4`
`⇔` \(\left[ \begin{array}{l}x-2=3\\x-2=-3\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=5\\x=-1\end{array} \right.\)
Vậy `x \in {5;-1}`
c) `128=(5-x)^7`
`⇔ 2^7=(5-x)^7`
`⇔ 5-x=2`
`⇔ x=3`
Vậy `x=3`
d) `1=(6-x)^{2014}`
`⇔ (1)^{2014}=(6-x)^{2014}`
`⇔` \(\left[ \begin{array}{l}1=6-x\\-1=6-x\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=5\\x=7\end{array} \right.\)
Vậy `x \in {5;7}`
