Question

Tính\(\left[x+2015\right]^7=\left[x+2015\right]^5\)

tìm x

Answer 1

\(\left(x+2015\right)^7=\left(x+2015\right)^5\)

\(\left(x+2015\right)^7-\left(x+2015\right)^5=0\)

\(\left(x+2015\right)^5.\left(x+2015\right)^2-\left(x+2015\right)^5=0\)

\(\left(x+2015\right)^5\left[\left(x+2015\right)^2-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}\left(x-2015\right)^5=0\\\left(x+2015\right)^2-1=0\end{cases}\Rightarrow\orbr{\begin{cases}x=2015\\x=-2016;-2014\end{cases}}}\)

Vậy x = { - 2016; - 2014; 2015 }

Answer 2

x=-2015