a/ => X. (3,1+6,9)=25
=> X.10=25
=> X=25:10=5/2
b/ X.3 = 7,65-31,5.0,1
=> 3X=4,5
=> X=4,5:3 = 1,5

Đinh Thị Hải Anh làm kiểu j ấy

1) \(31,5\cdot0,1+3x=7,65\)

\(\Leftrightarrow3,15+3x=7,65\)

\(\Leftrightarrow3x=4,5\)

\(\Leftrightarrow x=1,5\)

b)\(\frac{3}{8}+\left(x-\frac{5}{24}\right):\frac{2}{3}=1\)

\(\Leftrightarrow\left(x-\frac{5}{24}\right):\frac{2}{3}=\frac{5}{8}\)

\(\Leftrightarrow x-\frac{5}{24}=\frac{5}{12}\)

\(\Leftrightarrow x=\frac{5}{8}\)

1.  \(31,5.0,1+3x=7,65\)

\(\Leftrightarrow3,15+3x=7,65\)

\(\Leftrightarrow3x=4,5\)

\(\Leftrightarrow x=1,5\)

2. \(\frac{3}{8}+\left(x-\frac{5}{24}\right):\frac{2}{3}=1\)

\(\Leftrightarrow\left(x-\frac{5}{24}\right):\frac{2}{3}=\frac{5}{8}\)

\(\Leftrightarrow x-\frac{5}{24}=\frac{5}{8}.\frac{2}{3}\)

\(\Leftrightarrow x-\frac{5}{24}=\frac{5}{12}\)

\(\Leftrightarrow x=\frac{5}{8}\)

a) \(x.3,1+x.6,9+5,4=30,4\)

\(x.\left(3,1+6,9\right)+5,4=30,4\)

\(x.10+5,4=30,4\)

\(x.10=30,4-5,4\)

\(x.10=25\)

\(x=25\div10\)

\(x=\frac{5}{2}\)

b) \(31,5.0,1+x.3=7,65\)

\(3,15+x.3=7,65\)

a: =>10x=25

hay x=2,5

b: =>3x=7,65-3,15=4,5

hay x=1,5

\(a,x\times3,1+x\times6,9+5,4=30,4\)

\(x\times3,1+x\times6,9=30,4+5,4\)

\(x\times3,1+x\times6,9=35,8\)

\(x\times\left(3,1+6,9\right)=35,8\)

\(x\times10=35,8\)

\(x=35,8:10\)

\(x=3,58\)

mày ơi tao đúp rồi

\(31,5\times0,1+x\times3=7,65\)

\(3,15+x\times3=7,65\)

\(x\times3=7,65-3,15\)

\(x\times3=4,5\)

\(x=4,5:3\)

\(x=1,5\)

17,5 : 1,52 = 875/76

72,45 : 3,45 = 21

562,5 : 4,5 = 125

91,08 : 1,8 = 50.6

 875/76

 21

125

50.6

\(17,5:1,52\approx11,5\)

\(72,45:3,45=21\)

\(562,5:4,5=125\)

\(91,08:1,8=50,6\)

a) 45.63

b) 41.87

c) 13.804

d) 25,3