a, 4/7+3/7:x=-3 => 4/7+x=3/7:-3 => 4/7+x=-1/7 => x=-1/7-4/7 => x=-5/7
b,lx-1/5l=1 4/5 => lx-1/5l=9/5
th1: x-1/5=9/5 => x=9/5+1/5 => x=2
th2: x-1/5=9/5 => x=-9/5+1/5 => x=-8/5
c,(0,25.x):3=5/6:0,125
=> (0,25.x):3=5/6:1/8
=>(0,25.x):3=20/3
=>0,25.x=20/3.3
=>0,25.x=20
=>x=20:0,25
=>x=80
mik lm xog r
\(\dfrac{4}{7}+\dfrac{3}{7}:x=-3\)
\(\dfrac{3}{7}:x=\left(-3\right)+\left(\dfrac{-4}{7}\right)=\dfrac{-25}{7}\)
\(x=\dfrac{3}{7}:\left(\dfrac{-25}{7}\right)=\dfrac{-3}{25}\)
\(\left|x-\dfrac{1}{5}\right|=1\dfrac{4}{5}\)
\(\left|x-\dfrac{1}{5}\right|=\dfrac{9}{5}\)
\(\text{Vậy }x-\dfrac{1}{5}=\dfrac{9}{5}\)
\(x\) \(=\dfrac{9}{5}+\dfrac{1}{5}=2\)
\(\text{hoặc }x-\dfrac{1}{5}=\dfrac{-9}{5}\)
\(x\) \(=\left(\dfrac{-9}{5}\right)+\dfrac{1}{5}=\dfrac{-8}{5}\)
\(\Rightarrow x\in\left\{2;\left(\dfrac{-8}{5}\right)\right\}\)
\(\left(0,25x\right):3=\dfrac{5}{6}:0,125\)
\(\left(\dfrac{1}{4}x\right):3=\dfrac{5}{6}:\dfrac{1}{8}\)
\(\left(\dfrac{1}{4}x\right):3=\dfrac{20}{3}\)
\(\left(\dfrac{1}{4}x\right)\) \(=\dfrac{20}{3}.3=20\)
\(x\) \(=20.4=80\)
