Question

tìm x, biết: a) | 2x-4|=|3x+5|

b) |3x+5|= x-2

c) |x-1|+|x-2|+|x-3| = 5

Answer 1

a) =>\(\left\{{}\begin{matrix}2x-4=3x+5\\2x-4=-3x-5\end{matrix}\right.\)

Với 2x - 4 = 3x + 5 Với 2x - 4 = -3x - 5

=>2x - 3x = 5 + 4 =>2x + 3x = -5 + 4

-1x = 9 5x = -1

x = 9 : (-1) x = \(\dfrac{-1}{5}\)

x = -9

Answer 2

a: =>3x+5=2x-4 hoặc 3x+5=4-2x

=>x=-9 hoặc 5x=-1

=>x=-9 hoặc x=-1/5

b: \(\Leftrightarrow\left\{{}\begin{matrix}x>=2\\\left(3x+5-x+2\right)\left(3x+5+x-2\right)=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x>=2\\\left(2x+7\right)\left(4x+3\right)=0\end{matrix}\right.\Leftrightarrow x\in\varnothing\)