x+1/2 =8/x+1
=>(x+1).(x+1)=8.2
=>(x+1)^2=16
=>(x+1)^2=4^2
trường hợp1: x+1=4
x=3
trường hợp 2:x+1=-4
x=-5
suy ra (x+1)^2 = 16
(x+1)^2 = 4^2
suy ra x+1=4
x=4-1=3
\(\frac{x+1}{2}=\frac{8}{x+1}\Rightarrow\left(x+1\right)\left(x+1\right)=8\cdot2\)
\(\left(x+1\right)^2=16=4^2\)
\(x+1=4\Rightarrow x=3\)
\(\frac{x+1}{2}=\frac{8}{x+1}\)
\(\Rightarrow\left(x+1\right)\left(x+1\right)=8.2\)
\(\Rightarrow\left(x+1\right)^2=16\)
\(\Rightarrow\orbr{\begin{cases}x+1=4\\x+1=-4\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=3\\x=-5\end{cases}}\)
Mà \(x\in N\Rightarrow x=3\)
Vậy \(x=3\)
Chúc bạn học tốt !!!
suy ra (x+1)^2=16=(+-4)
*)x+1=4 suy ra x=3
*)x+1=-4 suy ra x=-5
vì x thuộc N nên x =3