Question

tìm x thuộc z biết 1<|x-4|<4

Answer 1

\(1<|x-4|<4 \Leftrightarrow 1<(x-4)^2<16 \\ \Leftrightarrow 1<x^2-8x+16<16 \\ \Leftrightarrow \left\{\begin{matrix} x^2-8x+16>1\\ x^2-8x+16<16 \end{matrix}\right. \\ \Leftrightarrow \left\{\begin{matrix} x<3,x>5\\ 0<x<8 \end{matrix}\right. \\ \Leftrightarrow 0<x<3;5<x<8\)

KL: .............................