Bài 2:
a) Vì \(\left|x\right|\)=\(\dfrac{3}{8}\)=>x\(\in\)\(\left\{\pm\dfrac{3}{8}\right\}\)
b)\(\left|x+5\right|\)-\(\dfrac{1}{6}\)=\(\dfrac{1}{3}\)
=> \(\left|x+5\right|\) = \(\dfrac{1}{3}\)+\(\dfrac{1}{6}\)
=>\(\left|x+5\right|\) = \(\dfrac{1}{2}\)
=>\(\left|x+5\right|\) = \(\left\{\pm\dfrac{1}{2}\right\}\)
=>\(\left\{{}\begin{matrix}x+5=\dfrac{1}{2}\\x+5=-\dfrac{1}{2}\end{matrix}\right.\) =>\(\left\{{}\begin{matrix}x=\dfrac{1}{2}-5\\x=-\dfrac{1}{2}-5\end{matrix}\right.\)=>\(\left\{{}\begin{matrix}x=-\dfrac{9}{2}\\x=-\dfrac{11}{2}\end{matrix}\right.\)
Vậy x\(\in\) \(\left\{-\dfrac{9}{2};-\dfrac{11}{2}\right\}\)
Tick cho mình nha!!!
Bài 3:
5x=3y
nên x/3=y/5
Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:
\(\dfrac{x}{3}=\dfrac{y}{5}=\dfrac{x-y}{3-5}=\dfrac{-5}{2}\)
=>x=-15/2; y=-25/2
