Question

Tìm x :

I x-4I -x +2=0

 

Answer 1

|x - 4| - x + 2 = 0

=> |x - 4| = x - 2

+ Với x < 4 thì |x - 4| = 4 - x

Ta có: 4 - x = x - 2

=> -x - x = -2 - 4

=> -2x = -6

=> x = -6 : (-2) = 3, thỏa mãn x < 4

+ Với \(x\ge4\) thì |x - 4| = x - 4

Ta có: x - 4 = x - 2

=> x - x = -2 + 4

=> 0 = 2, vô lý

Vậy x = 3

Answer 2

|x-4|-x+2=0

\(\Leftrightarrow\left|x-4\right|=x-2\)

\(\Leftrightarrow x-4=\pm\left(x-2\right)\)

Nếu \(x-4=x-2\)

\(\Leftrightarrow-4=-2\left(loai\right)\)

Nếu \(x-4=-\left(x-2\right)\)

\(\Leftrightarrow x-4=-x+2\)

\(\Leftrightarrow2x=6\)

\(\Leftrightarrow x=3\left(tm\right)\)

Vậy x=3