`a, x = -3 xx 6 : 4 = -9/2`
`b, x = 5 xx -20 : 15 = -20/3`
`c, 3x + 33 = 28 - 2x`
`<=> 5x = -5`
`<=> x = -1`
\(a,\dfrac{x}{6}=-\dfrac{3}{4}\\ \Rightarrow x=\dfrac{\left(-3\right).6}{4}=-\dfrac{9}{2}\\ b,\dfrac{5}{x}=\dfrac{15}{-20}\)
điều kiện : \(x\ne0\)
\(\Rightarrow x=\dfrac{5.\left(-20\right)}{15}=-\dfrac{20}{3}\left(thoaman\right)\)
\(c,đk:x\ne14\\ \Rightarrow3.\left(x+11\right)=2.\left(14-x\right)\\ \Rightarrow3x+33=28-2x\\ \Rightarrow5x=-5\\ \Rightarrow x=-1\left(thoaman\right)\)
a: x/6=-3/4
=>x=-3/4*6=-18/4=-9/2
b: 5/x=15/-20
=>5/x=-3/4
=>x=-5*4/3=-20/3
c: (x+11)/(14-x)=2/3
=>3x+33=28-2x
=>5x=-5
=>x=-1
