Bài 6:
a: =>x=27:3/4=36
b: =>x=11/3x8/11=3/8
c: =>2/3x-1/2=5/6
=>2/3x=4/3
hay x=2
d: =>1/4x=3+1+2/3=4+2/3=14/3
=>x=56/3
Bài 7:
a:9/63=1/7
b: -63/81=-7/9
c: \(\dfrac{3\cdot\left(-5\right)}{27\cdot15}=\dfrac{-1}{27}\)
d: \(\dfrac{9\cdot5-9\cdot3}{18}=\dfrac{9\cdot2}{18}=1\)
e: \(=\dfrac{11\cdot\left(5-1\right)}{22}=\dfrac{11\cdot4}{22}=2\)
f: \(=\dfrac{15\left(6-4\right)}{15}=2\)
Bài 5:
m, ( x - 4 ) . ( 3 - x ) = 0
\(\left[{}\begin{matrix}x-4=0\\3-x=0\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=4\\x=3\end{matrix}\right.\)
h, 2,5x - 8 = 2x + 3
\(\Leftrightarrow\) 2,5x - 2x = 3 + 8
\(\Leftrightarrow\) 0,5x = 11
\(\Leftrightarrow x=\dfrac{11}{0,5}=22\)
n, 2. ( x - 5 ) + 4 = 2
\(\Leftrightarrow2.\left(x-5\right)=-2\\ \Leftrightarrow x-5=-1\\ \Leftrightarrow x=-1+5=4\)
Bài 6:
\(a,x=27:\dfrac{3}{4}=27.\dfrac{4}{3}=36\)
\(b,x=\dfrac{11}{3}.\dfrac{8}{11}=\dfrac{8}{3}\)
\(c,\dfrac{2}{3}x=\dfrac{5}{6}+\dfrac{1}{2}=\dfrac{4}{3}\\ \Rightarrow x=\dfrac{4}{3}.\dfrac{3}{2}=2\)
\(d,25\%.x-1\dfrac{2}{3}=3\)
\(25\%.x=3+5=8\\ \Rightarrow x=\dfrac{8}{25\%}=32\)
