`1/2x + 3/4 = -3/10`
`1/2x = -3/10 - 3/4`
`1/2x = -21/20`
`=> x = -21/10`
Vậy `x = -21/10`
\(\dfrac{1}{2}x+\dfrac{3}{4}=-\dfrac{3}{10}\)
\(\dfrac{1}{2}x=\left(-\dfrac{3}{10}\right)-\dfrac{3}{4}\)
\(\dfrac{1}{2}x=\left(-\dfrac{6}{20}\right)-\dfrac{15}{20}\)
\(\dfrac{1}{2}x=-\dfrac{21}{20}\)
\(x=\left(-\dfrac{21}{20}\right):\dfrac{1}{2}\)
\(x=\left(-\dfrac{21}{20}\right)\cdot2\)
\(x=-\dfrac{42}{20}\)
\(x=-\dfrac{21}{10}\)