giupsp t voiii
a.
\(\dfrac{3}{4}+\dfrac{1}{4}:x=-3\)
\(\dfrac{1}{4}:x=-3-\dfrac{3}{4}\)
\(\dfrac{1}{4}:x=-\dfrac{15}{4}\)
\(x=\dfrac{1}{4}:\left(-\dfrac{15}{4}\right)\)
\(x=-\dfrac{1}{15}\)
b.
\(\dfrac{4}{7}x-x=\dfrac{-9}{14}\)
\(\Leftrightarrow\left(\dfrac{4}{7}-1\right)x=\dfrac{-9}{14}\)
\(\Leftrightarrow-\dfrac{3}{7}x=-\dfrac{9}{14}\)
\(\Leftrightarrow x=-\dfrac{9}{14}:\left(-\dfrac{3}{7}\right)\)
\(\Leftrightarrow x=\dfrac{3}{2}\)
c.
\(\dfrac{1}{2}x+\dfrac{3}{5}x=\dfrac{-2}{3}\)
\(\Leftrightarrow\left(\dfrac{1}{2}+\dfrac{3}{5}\right)x=-\dfrac{2}{3}\)
\(\Leftrightarrow\dfrac{11}{10}x=-\dfrac{2}{3}\)
\(\Leftrightarrow x=-\dfrac{2}{3}:\dfrac{11}{10}\)
\(\Leftrightarrow x=-\dfrac{20}{33}\)
Lời giải:
n. $\frac{1}{4}:x=-3-\frac{3}{4}=\frac{-15}{4}$
$x=\frac{1}{4}: \frac{-15}{4}=\frac{-1}{15}$
o.
$\frac{4}{7}x-x=\frac{-9}{14}$
$x(\frac{4}{7}-1)=\frac{-9}{14}$
$x.\frac{-3}{7}=\frac{-9}{14}$
$x=\frac{-9}{14}: \frac{-3}{7}=\frac{3}{2}$
p.
$\frac{1}{2}x+\frac{3}{5}x=\frac{-2}{3}$
$x(\frac{1}{2}+\frac{3}{5})=\frac{-2}{3}$
$x.\frac{11}{10}=\frac{-2}{3}$
$x=\frac{-2}{3}: \frac{11}{10}=\frac{-20}{33}$
