Question

Mọi người giúp mình với

Answer 1

\(a,\Rightarrow\dfrac{4}{7}x=-\dfrac{2}{21}\\ \Rightarrow x=-\dfrac{2}{21}\cdot\dfrac{7}{4}=-\dfrac{1}{6}\\ b,\Rightarrow\dfrac{1}{4}:x=-\dfrac{7}{20}\\ \Rightarrow x=\dfrac{1}{4}:\left(-\dfrac{7}{20}\right)=-\dfrac{5}{7}\\ c,\Rightarrow\left|\dfrac{1}{2}x-\dfrac{3}{4}\right|=-3+7=4\\ \Rightarrow\left[{}\begin{matrix}\dfrac{1}{2}x-\dfrac{3}{4}=4\\\dfrac{3}{4}-\dfrac{1}{2}x=4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}\dfrac{1}{2}x=\dfrac{19}{4}\\\dfrac{1}{2}x=-\dfrac{13}{4}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{19}{2}\\x=-\dfrac{13}{2}\end{matrix}\right.\)

\(d,\Rightarrow\left|\dfrac{1}{2}-x\right|=6-\dfrac{2}{5}=\dfrac{28}{5}\\ \Rightarrow\left[{}\begin{matrix}\dfrac{1}{2}-x=\dfrac{28}{5}\\x-\dfrac{1}{2}=\dfrac{28}{5}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=-\dfrac{51}{10}\\x=\dfrac{61}{10}\end{matrix}\right.\\ e,ĐK:x\ge0\\ PT\Leftrightarrow\sqrt{x}=3+1=4\Leftrightarrow x=16\left(tm\right)\)