Question

Tìm x \(\in\) N:

\(\dfrac{x+1}{2}\)=\(\dfrac{8}{x+1}\)

Answer 1

Ta có: (x+1)(x+1)=2*8

(x+1)^2=16

Suy ra: (x+1)^2=4^2

x+1=4

x=4-1

x=3

Answer 2

Nhân chéo vào bạn

Tick nha

Answer 3

\(\dfrac{x+1}{2}=\dfrac{8}{x+1}\)

Ta có : \(\left(x+1\right)\times\left(x+1\right)=2\times8\)

\(\left(x+1\right)^2=16\)

\(\left(x+1\right)^2=4^2\)hoặc \(\left(-4\right)^2\)

\(\Rightarrow\left[{}\begin{matrix}x+1=4\\x+1=-4\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=4-1\\x=\left(-4\right)-1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-5\end{matrix}\right.\)

Vậy \(\left[{}\begin{matrix}x=3\\x=-5\end{matrix}\right.\)