Question

cho x,y,z thuộc N*

\(M=\frac{x}{x+y+z}+\frac{y}{x+y+z}+\frac{z}{y+z+t}+\frac{t}{x+z+t}\)có giá trị không phải là số tự nhiên

Answer 1

\(3\left(x-5\right)^2-5=22\)

\(3\left(x-5\right)^2=22+3\)

   \(\left(x-5\right)^2=27.3\)

    \(\left(x-5\right)^2=81\)

    \(\left(x-5\right)^2=9^2\)

    \(\left(x-5\right)=9\)

    \(x=9+5\)

    \(x=14\)

Đúng nha

Answer 2

\(3\left(x-5\right)^2-5=22\)

\(3\left(x-5\right)^2=22+5\)

\(3\left(x-5\right)^2=27\)

\(\left(x-5\right)^2=27:3\)

\(\left(x-5\right)^2=9\)

\(\left(x-5\right)^2=3^2\)

\(x-5=3\)

\(x=3+5\)

\(x=8\)