Câu 2:
\(a,x+\dfrac{2}{5}=\dfrac{1}{6}\) \(b,\dfrac{1}{3}-\dfrac{5}{3}.x=\dfrac{2}{7}\)
\(x=\dfrac{1}{6}-\dfrac{2}{5}\) \(\dfrac{5}{3}.x=\dfrac{1}{3}-\dfrac{2}{7}\)
\(x=-\dfrac{7}{30}\) \(\dfrac{5}{3}.x=\dfrac{1}{21}\)
Vậy \(x=-\dfrac{7}{30}\) \(x=\dfrac{1}{21}:\dfrac{5}{3}\)
\(x=\dfrac{1}{35}\)
Vậy \(x=\dfrac{1}{35}\)
a, ⇒ \(x=\dfrac{1}{6}-\dfrac{2}{5}\)
\(\Rightarrow x=\dfrac{5}{30}-\dfrac{12}{30}\)
\(\Rightarrow x=-\dfrac{7}{30}\)
b, \(\Rightarrow\dfrac{5}{3}x=\dfrac{1}{3}-\dfrac{2}{7}\)
⇒ \(\dfrac{5}{3}x=\dfrac{7}{21}-\dfrac{6}{21}\)
\(\Rightarrow\dfrac{5}{3}x=\dfrac{1}{21}\)
\(\Rightarrow x=\dfrac{1}{21}:\dfrac{5}{3}\)
\(\Rightarrow x=\dfrac{1}{21}.\dfrac{3}{5}=\dfrac{1}{35}\)
c, \(\Rightarrow\left|x-\dfrac{2}{5}\right|=3+\dfrac{1}{4}\)
\(\Rightarrow\left|x-\dfrac{2}{5}\right|=\dfrac{13}{4}\)
\(\Rightarrow\left[{}\begin{matrix}x-\dfrac{2}{5}=\dfrac{13}{4}\\x-\dfrac{2}{5}=-\dfrac{13}{4}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{73}{20}\\x=-\dfrac{57}{20}\end{matrix}\right.\)
d, ⇒ x.x = 2.8
⇒ x2 = 16
⇒ x2 = (\(\pm4\))2
⇒ x = \(\pm4\)
A.x=1/6-2/5
x=5/12
B5/2.x=2/7+1/3
5/2.x=1/3
x=1/3:5/2
x=4/15
C.x-2/5=3+1/4
x-2/5=13/4
Dx=4
x=4 em ko chắc em mới học lớp 6 à