Question

[Đinh Bảo Ngọc]

|x+12|+|x+13|+|x+14|=4x

Cho mink hỏi x bằng bn

Có cách giả nha!!!!!!! Cảm ơn các bạn nhìu!!!!

Answer 1

[Chim Hoạ Mi]

|x+12|+|x+13|+|x+14|=4x

|x+12|+|x+13|+|x+14| luôn\(\ge\) 0=>x \(\ge\)0

|x+12|+|x+13|+|x+14| là số dương  hay|x+12|+|x+13|+|x+14| =x+12+x+13+x+14=4x

x+12+x+13+x+14=4x

3x+(12+13+14)=4x

4x-3x=12+13+14

x=39

Answer 2

[zZz Cool Kid_new zZz]

Do \(\left|x+12\right|\ge0,\left|x+13\right|\ge0,\left|x+14\right|\ge0\)

\(\Rightarrow\left|x+12\right|+\left|x+13\right|+\left|x+14\right|>0\)

Do VP>0 suy ra VT>0

Hay \(4x>0\)

\(\Rightarrow x>0\)

Khi đó:\(\left|x+12\right|+\left|x+13\right|+\left|x+14\right|=4x\)

\(\Leftrightarrow3x+39=4x\)(vì x>0)

\(\Rightarrow x=39\)