Question

BÀI 1: TÌM X:

a)  I x - 1 I = 0

b) -11 . I 3x - 1I = -22

c) I x I <2

Answer 1

a, !x-1!=0

\(\Rightarrow x-1=0\)

\(\Rightarrow x=0+1\)

\(\Rightarrow x=1\)

Vậy x=1

b,-11.!3x-1!=-22

\(\Rightarrow!3x-1!=-22:\left(-11\right)\)

\(\Rightarrow!3x-1!=2\)

\(\Rightarrow\orbr{\begin{cases}3x-1=2\\3x-1=-2\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}3x=2+1\\3x=-2+1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}3x=3\\3x=-1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=3:3\\x=-1:3\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=1\\x=\frac{-1}{3}\end{cases}}\)

Vậy \(\orbr{\begin{cases}x=1\\x=-\frac{1}{3}\end{cases}}\)

c, !x!<2

\(\Rightarrow x\in\left\{-1;0;1\right\}\)

Vậy \(x\in\left\{-1;0;1\right\}\)

Hok tốt nhé!!

Answer 2

A ) 

| x - 1 | = 0 

  x        = 0 + 1 

  x        = 1 

B ) 

-11 . | 3x - 1 | = -22 

         | 3x - 1 | = -22 : ( -11 ) 

         | 3x - 1 | = 2 

           3x        = 2 + 1 

           3x        = 3 

             x        = 3 : 3 

             x        = 1