`#3107.101107`
`3.`
`a,`
`(x + 2,8) \div 5 = 0,3`
\(\Rightarrow x+2,8=0,3\cdot5\)
\(\Rightarrow x+2,8=1,5\)
\(\Rightarrow x=1,5-2,8\)
\(\Rightarrow x=-1,3\)
Vậy, `x = -1,3`
`b,`
\(\left(x+\dfrac{5}{6}\right)\cdot2\dfrac{2}{5}-1\dfrac{1}{4}=35\%\)
\(\Rightarrow\left(x+\dfrac{5}{6}\right)\cdot\dfrac{12}{5}=0,35+\dfrac{5}{4}\)
\(\Rightarrow x+\dfrac{5}{6}=\dfrac{2}{3}\)
\(\Rightarrow x=\dfrac{2}{3}-\dfrac{5}{6}\)
\(\Rightarrow x=-\dfrac{1}{6}\)
Vậy, \(x=-\dfrac{1}{6}\)
`c,`
\(\dfrac{1-2x}{2}=\dfrac{-1,5}{3}\\ \Rightarrow\left(1-2x\right)\cdot3=2\cdot\left(-1,5\right)\\
\Rightarrow1-2x=-3\div3\\
\Rightarrow1-2x=-1\\
\Rightarrow2x=1-\left(-1\right)\\
\Rightarrow2x=2\\
\Rightarrow x=1\)
Vậy, `x = 1`
`d,`
`1,4x - x = -8,844`
$\Rightarrow 0,4x = -8,844$
$\Rightarrow x = -8,844 \div 0,4$
$\Rightarrow x = -22,11$
Vậy, `x = -22,11`
`e,`
`x - 5,01 = 7,02 - 2 * 1,5`
$\Rightarrow x - 5,01 = 7,02 - 3$
$\Rightarrow x - 5,01 = 4,02$
$\Rightarrow x = 4,02 + 5,01$
$\Rightarrow x = 9,03$
Vậy, `x = 9,03.`