c)\(1-\left(x-\frac{1}{5}\right)^2=\frac{21}{25}\)
\(\Leftrightarrow\left(x-\frac{1}{5}\right)^2=\frac{4}{25}\)
\(\Leftrightarrow x-\frac{1}{5}=\frac{2}{5}\)
\(\Leftrightarrow x=\frac{3}{5}\)
d)\(\left|x+\frac{1}{3}\right|.3\frac{2}{5}=\frac{2}{5}\)
\(\Leftrightarrow\left|x+\frac{1}{3}\right|.\frac{17}{5}=\frac{2}{5}\)
\(\Leftrightarrow\left|x+\frac{1}{3}\right|=\frac{2}{17}\)
\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{3}=\frac{2}{17}\\x+\frac{1}{3}=-\frac{2}{17}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{11}{51}\\x=-\frac{23}{51}\end{cases}}}\)
#H
1-(x-1/5)2=21/25
(x-1/5)2=1-21/25
(x-1/5)2=4/25
(x-1/5)2=(2/5)2
x-1/5=2/5
x=2/5+1/5
x=3/5
k nha
Bài 2 :
a.
3 + 2x = 1
2x = 1 - 3
2x = - 2
x = - 2 : 2
x = - 1
Vậy x = - 1
b.
\(\frac{1}{5}+\frac{4}{5}\): x = - 1
\(\frac{4}{5}\): x = - 1 - \(\frac{1}{5}\)
\(\frac{4}{5}\): x = \(-\frac{6}{5}\)
x = \(\frac{4}{5}\): \(\left(-\frac{6}{5}\right)\)
x = \(-\frac{2}{3}\)
Vậy x = \(-\frac{2}{3}\)
c,
\(1-\left(x-\frac{1}{5}\right)^2=\frac{21}{25}\)
\(\left(x-\frac{1}{5}\right)^2=1-\frac{21}{25}\)
\(\left(x-\frac{1}{5}\right)^2=\frac{4}{25}\)
\(\left(x-\frac{1}{5}\right)^2=\left(\frac{2}{5}\right)^2\)hoặc \(\left(-\frac{2}{5}\right)^2\)
\(\Rightarrow\)\(x-\frac{1}{5}=\frac{2}{5}\)hoặc \(-\frac{2}{5}\)
\(\Rightarrow\)\(x=\frac{3}{5}\)hoặc \(-\frac{1}{5}\)
Vậy x \(\in\){ \(\frac{3}{5}\); \(-\frac{1}{5}\)}
