Question

tìm x bt \(\frac{x+1}{8}=\frac{8}{x+1}\left(x\ne1\right)\)

Answer 1

ta có

\(\frac{x+1}{8}=\frac{8}{x+1}\)

=> (x+1).(x+1)=8.8

=> (x+1)(x+1)=(7+1).(7+1)

=> x=7

Answer 2

\(\frac{x+1}{8}=\frac{8}{x+1}\)

\(\Rightarrow\left(x+1\right).\left(x+1\right)=8.8\)

\(\Rightarrow\left(x+1\right)^2=8^2\)

\(\Rightarrow x+1=8\)

\(\Rightarrow x=8-1\)

\(\Rightarrow x=7\)