Question

Rút gọn biểu thức : a) M= |x| + 2x ; b) N= 5x - |x| ; c) P= | x - 1 | + 2x-3 ; d) Q= 3x-4 - | 2x - 1 |

Answer 1

a) \(M=\left|x\right|+2x\)

\(\Rightarrow M=\left[{}\begin{matrix}x+2x=3x\left(x\ge0\right)\\-x+2x=x\left(x< 0\right)\end{matrix}\right.\)

b) \(N=5x-\left|x\right|\)

\(\Rightarrow N=\left[{}\begin{matrix}5x-x=4x\left(x\ge0\right)\\5x+x=6x\left(x< 0\right)\end{matrix}\right.\)

c) \(P=\left|x-1\right|+2x-3\)

\(\Rightarrow P=\left[{}\begin{matrix}x-1+2x-3=3x-4\left(x\ge0\right)\\1-x+2x-3=x-2\left(x< 0\right)\end{matrix}\right.\)

d) \(Q=3x-4-\left|2x-1\right|\)

\(\Rightarrow Q=\left[{}\begin{matrix}3x-4-2x+1=x-3\left(x\ge0\right)\\3x-4-1+2x=5x-5\left(x< 0\right)\end{matrix}\right.\)