3/4 + 1/4 : x = 2/5
1/4 : x = 3/4 - 2/5
1/4 : x = 15/20 - 8/20
1/4 : x = 7/20
x = 1/4 : 7/20
x = 1/4 x 20/7
x = 5/7
Vậy x = 5/7
\(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
\(\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}\)
\(\frac{1}{4}:x=-\frac{7}{20}\)
\(x=\frac{1}{4}:\left(\frac{-7}{20}\right)\)
\(x=\frac{-5}{7}\)
Vậy \(x=\frac{-5}{7}\)
3/4 + 1/4 : x = 2/5
1/4 : x = 2/5 - 3/4
1/4 : x = 8/20 - 15/20
1/4 : x = -7/20
x = 1/4 : (-7/20)
x = 1/4 . (-20/7)
x = -5/7
vậy x = -5/7
\(\text{Ta có: 3/4 + 1/4 : x = 2/5
}\)
\(\Rightarrow\)\(\text{1/4 : x = 3/4 - 2/5
}\)
\(\Rightarrow\)\(\text{1/4 : x = 15/20 - 8/20}\)
\(\Rightarrow\)\(\text{1/4 : x = 7/20}\)
\(\Rightarrow\)\(\text{x = 1/4 : 7/20}\)
\(\Rightarrow\)\(\text{x = 1/4 x 20/7
}\)
\(\Rightarrow\) \(\text{x = 5/7}\)
\(\text{Vậy x = 5/7 }\)
3/4 + 1/4 : x = 2/5
1/4 : x = 3/4 - 2/5
1/4 : x = 15/20 - 8/20
1/4 : x = 7/20
x = 1/4 : 7/20
x = 1/4 x 20/7
x = 5/7
Vậy x = 5/7
