Question

tìm x , biết :

a) \(\dfrac{7}{9}\)<\(\dfrac{13}{11}\)-x<\(\dfrac{15}{16}\)

b) |x-1|<2

Answer 1

a: =>\(\left\{{}\begin{matrix}\dfrac{13}{11}-x>\dfrac{7}{9}\\\dfrac{13}{11}-x< \dfrac{15}{16}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}-x>\dfrac{7}{9}-\dfrac{13}{11}=-\dfrac{170}{209}\\-x< \dfrac{15}{16}-\dfrac{13}{11}=-\dfrac{43}{176}\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x< \dfrac{170}{209}\\x>\dfrac{43}{176}\end{matrix}\right.\)

b: =>-2<x-1<2

=>-1<x<3