1. tìm x biết a) 1/3 + 2/3 : x= -7 b)2/3 : x = 1,4 - 12/5 c)(4,5 -2 . x ).11/7=11/14 d)3/4 . x =1/2 e)4/5 5/7 :x =1/6 f)6/-x = x/-24 g) (4 . x -5). (5/4 . x - 2) = 0 (lưu ý : dấu . là nhân )
Chào cả nhà, mình đang gặp chút vấn đề khó khăn và thực sự cần sự giúp đỡ của mọi người. Ai biết chỉ giúp mình với nhé!

a: \(\dfrac{1}{3}+\dfrac{2}{3}:x=-7\)

=>\(\dfrac{2}{3}:x=-7-\dfrac{1}{3}=-\dfrac{22}{3}\)

=>\(x=-\dfrac{2}{3}:\dfrac{22}{3}=-\dfrac{2}{3}\cdot\dfrac{3}{22}=-\dfrac{1}{11}\)

b: \(\dfrac{2}{3}:x=1,4-\dfrac{12}{5}\)

=>\(\dfrac{2}{3}\cdot x=1,4-2,4=-1\)

=>\(x=-1:\dfrac{2}{3}=-\dfrac{3}{2}\)

c: \(\left(4,5-2x\right)\cdot\dfrac{11}{7}=\dfrac{11}{14}\)

=>\(4,5-2x=\dfrac{11}{14}:\dfrac{11}{7}=\dfrac{7}{14}=0,5\)

=>2x=4,5-0,5=4

=>x=4/2=2

d: \(\dfrac{3}{4}\cdot x=\dfrac{1}{2}\)

=>\(x=\dfrac{1}{2}:\dfrac{3}{4}=\dfrac{1}{2}\cdot\dfrac{4}{3}=\dfrac{2}{3}\)

e: \(\dfrac{4}{5}+\dfrac{5}{7}:x=\dfrac{1}{6}\)

=>\(\dfrac{5}{7}:x=\dfrac{1}{6}-\dfrac{4}{5}=\dfrac{5-24}{30}=\dfrac{-19}{30}\)

=>\(x=-\dfrac{5}{7}:\dfrac{19}{30}=-\dfrac{5}{7}\cdot\dfrac{30}{19}=\dfrac{-150}{133}\)

f: \(\dfrac{6}{-x}=\dfrac{x}{-24}\)(ĐKXĐ: x<>0)

=>\(\dfrac{6}{x}=\dfrac{x}{24}\)

=>\(x^2=144\)

=>\(\left[{}\begin{matrix}x=12\left(nhận\right)\\x=-12\left(nhận\right)\end{matrix}\right.\)

g: \(\left(4x-5\right)\left(\dfrac{5}{4}x-2\right)=0\)

=>\(\left[{}\begin{matrix}4x-5=0\\\dfrac{5}{4}x-2=0\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}4x=5\\\dfrac{5}{4}x=2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=2:\dfrac{5}{4}=2\cdot\dfrac{4}{5}=\dfrac{8}{5}\end{matrix}\right.\)