\(\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\dfrac{9}{4}\)
\(=>\left[{}\begin{matrix}\dfrac{1}{5}-\dfrac{3}{2}x=\dfrac{3}{2}\\\dfrac{1}{5}-\dfrac{3}{2}x=-\dfrac{3}{2}\end{matrix}\right.\\ =>\left[{}\begin{matrix}\dfrac{3}{2}x=-\dfrac{13}{10}\\\dfrac{3}{2}x=\dfrac{17}{10}\end{matrix}\right.\\ =>\left[{}\begin{matrix}x=-\dfrac{13}{15}\\x=\dfrac{17}{15}\end{matrix}\right.\)
\(\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\dfrac{9}{4}\)
\(\Leftrightarrow\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\dfrac{3}{2}^2\)
\(\Leftrightarrow\dfrac{1}{5}-\dfrac{3}{2}x=\dfrac{3}{2}\)
\(\Leftrightarrow\dfrac{3}{2}x=\dfrac{1}{5}-\dfrac{3}{2}\)
\(\Leftrightarrow\dfrac{3}{2}x=-\dfrac{13}{10}\)
\(\Leftrightarrow x=-\dfrac{13}{15}\)
\(\left(\dfrac{1}{5}-\dfrac{3}{2}.x\right)^2=\dfrac{9}{4}\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(\dfrac{1}{5}-\dfrac{3}{2}.x\right)^2=\left(\dfrac{3}{2}\right)^2\\\left(\dfrac{1}{5}-\dfrac{3}{2}.x\right)^2=\left(-\dfrac{3}{2}\right)^2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\dfrac{1}{5}-\dfrac{3}{2}.x=\dfrac{3}{2}\\\dfrac{1}{5}-\dfrac{3}{2}.x=-\dfrac{3}{2}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{3}{2}.x=\dfrac{1}{5}-\dfrac{3}{2}\\\dfrac{3}{2}.x=\dfrac{1}{5}-\left(-\dfrac{3}{2}\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\dfrac{3}{2}.x=-\dfrac{13}{10}\\\dfrac{3}{2}.x=\dfrac{17}{10}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{13}{10}:\dfrac{3}{2}\\x=\dfrac{17}{10}:\dfrac{3}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{13}{15}\\x=\dfrac{17}{15}\end{matrix}\right.\)
Vậy ................
=(1/5-3/2x)=3/2
=> 1/5-3/2x=+-3/2
=> th1 : 1/5-3/2x=3/2
3/2x=1/5-3/2
3/2x=-13/10
x=-13/10:3/2
x=-13/15
th2 : 1/5-3/2x=-3/2
3/2x=1/5-(-3/2)
3/2x=17/10
x=17/10:3/2
x= 17/15
Vậy x \(\in\) (-13/15 hoặc 17/15 )
hôm trước vừa làm bài kiểm tra cô chữa bảo là vậy
\(c,\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\dfrac{9}{4}\)
\(\Rightarrow\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\left(\pm\dfrac{3}{2}\right)^2\)
\(\Rightarrow\left[{}\begin{matrix}\dfrac{1}{5}-\dfrac{3}{2}x=\dfrac{3}{2}\\\dfrac{1}{5}-\dfrac{3}{2}x=\dfrac{-3}{2}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}\dfrac{3}{2}x=\dfrac{-13}{10}\\\dfrac{3}{2}x=\dfrac{17}{10}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{-13}{15}\\x=\dfrac{17}{15}\end{matrix}\right.\)
