= 0,3 + 0,0(18) = 0,3 + 18 x 0,0(01) = 0,3 + 18 x 1/990 = 7/22 

\(0,3\left(18\right)=0,3+0,0\left(18\right)=\frac{3}{10}+\frac{1}{10}.0,\left(18\right)=\frac{3}{10}+\frac{1}{10}.18.0,\left(01\right)=\frac{3}{10}+\frac{1}{10}.18.\frac{1}{99}=\frac{7}{22}\)

18 - x * 0,3 = 15

x * \(\frac{3}{10}=3\)

x=10 

đúng cho mk nha!

18-x=15:0.3

18-x=50

=>x=18-50

=>x=(-32)

=-32 nhaaaa

minh tra loi dau tien do

\(0,3\left(18\right)=0,3+0,0\left(18\right)=\frac{1}{10}+0,\left(18\right).0,1=\frac{1}{10}+\frac{18}{99}.\frac{1}{10}=\frac{1}{10}+\frac{18}{990}=\frac{13}{110}\)

ta có \(0,3\left(18\right)=\frac{1}{10}\times3,\left(18\right)=\frac{1}{10}\left(3+0,\left(18\right)\right)=\frac{1}{10}\left(3+\frac{1}{99}.18\right)=\frac{1}{10}\left(3+\frac{2}{11}\right)=\frac{1}{10}\times\frac{35}{11}=\frac{7}{22}\)

                                               Vậy 0,3(18)=\(\frac{7}{22}\)

y=1/10*(3+18/99)

y=1/10*35/11

y=7/22

->22*y=22*7/22=7

Vay 22*y=7

y=0,3(18)=7/22

=>22y=7