1,5

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4,5 : 0,3  =  2,25 : (0,1.x)

        15   = 2,25 : (0,1.x)

15 : 2,25  = 0,1.x

      20/3   = 0,1.x

20/3 : 0,1 = x

      200/3 = x

Ta có: 4,5 : 0,3 = 2,25 : (0,1 . x)

=> 4,5 . (0,1. x) = 2,25 . 0,3

=> 0,45 . x         = 0,675

=> x = 0,675 : 0,45

=> x = 1,5

Vậy x = 1,5

a.=> \(\frac{\left(\frac{1}{3}\right).x}{\frac{2}{3}}=\frac{\frac{7}{4}}{\frac{2}{5}}\)

=> \(\frac{1}{3}.x=\frac{7}{4}.\frac{2}{3}:\frac{2}{5}\)

=>\(\frac{1}{3}.x=\frac{35}{12}\)

=> x\(=\frac{35}{12}:\frac{1}{3}\)

Vậy x=\(\frac{35}{4}\).

b. => \(\frac{4,5}{0,3}=\frac{2,25}{0,1.x}\)

=>\(0,1.x=\frac{2,25.0,3}{4,5}\)

=>\(0,1.x=0,15\)

=>\(x=0,15:0,1\)

Vậy x=1,5

c. =>\(\frac{8}{\frac{1}{4}.x}=\frac{2}{0,02}\)

=>\(\frac{1}{4}.x=\frac{8.0,02}{2}\)

=>\(\frac{1}{4}.x=0,08\)

=>\(x=0,08:\frac{1}{4}\)

Vậy x=0,32.

d. =>\(\frac{3}{\frac{9}{4}}=\frac{\frac{3}{4}}{6.x}\)

=>\(3.6x=\frac{9}{4}.\frac{3}{4}\)

=>\(18x=\frac{27}{16}\)

=>\(x=\frac{27}{16}:18\)

Vậy x=\(\frac{3}{32}\)

a) \(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{7}{4}:\frac{2}{5}\)

\(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{35}{8}\)

\(\Rightarrow\frac{1}{3}.x=\frac{35}{8}.\frac{2}{3}\)

\(\Rightarrow\frac{1}{3}.x=\frac{35}{12}\)

\(\Rightarrow x=\frac{35}{12}:\frac{1}{3}\)

\(\Rightarrow x=\frac{35}{4}\)

Vậy \(x=\frac{35}{4}\)

a) x= \(\frac{35}{4}\)

\(a.\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{7}{4}:\frac{2}{5}\)

    \(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{35}{8}\)

          \(\left(\frac{1}{3}.x\right)=\frac{35}{8}.\frac{2}{3}\)

          \(\left(\frac{1}{3}.x\right)=\frac{35}{12}\)

                    \(x=\frac{35}{12}:\frac{1}{3}\)

                    \(x=\frac{35}{4}\)

\(b.4,5:0,3=2,25:\left(0,1.x\right)\)

\(\Rightarrow2,25:\left(0,1.x\right)=4,5:0,3\)

     \(2,25:\left(0,1.x\right)=15\)

     \(2,25:\left(0,1.x\right)=2,25:15\)

                \(\left(0,1.x\right)=0,15\)

                          \(x=0,15:0,1\)

                          \(x=1,5\)

\(c.8:\left(\frac{1}{4}.x\right)=2:0,02\)

   \(8:\left(\frac{1}{4}.x\right)=100\)

        \(\left(\frac{1}{4}.x\right)=8:100\)

        \(\left(\frac{1}{4}.x\right)=\frac{2}{25}\)

                  \(x=\frac{2}{25}:\frac{1}{4}\)

                  \(x=\frac{8}{25}\)

\(d.3:\frac{9}{4}=\frac{3}{4}:\left(6.x\right)\)

\(\Rightarrow\frac{3}{4}:\left(6.x\right)=3:\frac{9}{4}\)

     \(\frac{3}{4}:\left(6.x\right)=\frac{4}{3}\)

           \(\left(6.x\right)=\frac{3}{4}:\frac{4}{3}\)

          \(\left(6.x\right)=\frac{9}{16}\)

                \(x=\frac{9}{16}:6\)

                \(x=\frac{3}{32}\)

 ^...^ ^_^

p toán 5 ko

a)4,5:0,3=2,25:(0,1.x)

   2,25:(0,1.x)=15

   0,1.x=0,15

   x=0,15:0,1

   x=1,5

Vậy x=1,5

b)8:\(\left(\frac{1}{4}.x\right)\)=2:0,02

   8:\(\left(\frac{1}{4}.x\right)\)=100

       \(\left(\frac{1}{4}.x\right)\)=\(\frac{8}{100}\)

        x=\(\frac{8}{100}\):\(\frac{1}{4}\)

         x=\(\frac{8}{25}\)

Vậy x=\(\frac{8}{25}\)

c)\(3:2\frac{1}{4}=\frac{3}{4}:\left(6.x\right)\)

   \(\frac{3}{4}:\left(6.x\right)=\frac{4}{3}\)

    6.x=\(\frac{3}{4}:\frac{4}{3}\)

    6.x=\(\frac{9}{16}\)

    x=\(\frac{9}{16}\):6

    x=\(\frac{3}{32}\)

Vậy x=\(\frac{3}{32}\)

a.

\(4,5\div0,3=2,25\div\left(0,1\times x\right)\)

\(2,25\div\left(0,1\times x\right)=15\)

\(0,1\times x=\frac{2,25}{15}\)

\(0,1\times x=0,15\)

\(x=\frac{0,15}{0,1}\)

\(x=1,5\)

b.

\(8\div\left(\frac{1}{4}\times x\right)=2\div0,02\)

\(8\div\left(\frac{1}{4}\times x\right)=100\)

\(\frac{1}{4}\times x=\frac{8}{100}\)

\(\frac{1}{4}\times x=\frac{2}{25}\)

\(x=\frac{2}{25}\div\frac{1}{4}\)

\(x=\frac{2}{25}\times4\)

\(x=\frac{8}{25}\)

c.

\(3\div2^1_4=\frac{3}{4}\div\left(6\times x\right)\)

\(\frac{3}{4}\div\left(6\times x\right)=3\div2,25\)

\(\frac{3}{4}\div\left(6\times x\right)=\frac{4}{3}\)

\(6\times x=\frac{3}{4}\div\frac{4}{3}\)

\(6\times x=\frac{3}{4}\times\frac{3}{4}\)

\(6\times x=\frac{9}{16}\)

\(x=\frac{9}{16}\div6\)

\(x=\frac{9}{16}\times\frac{1}{6}\)

\(x=\frac{3}{32}\)

Trả lời :

\(0,1+0,2+0,3+...+0,x=4,5\)

\(0,1\times1+0,1\times2+0,1\times3+...+0,1\times x=4,5\)

\(0,1\times\left(1+2+3+...+x\right)=4,5\)

\(1+2+3+...+x=4,5:0,1\)

\(1+2+3+...+x=45\)

\(\left(x+1\right)\times x:2=45\)

\(\left(x+1\right)\times x=45\times2\)

\(\left(x+1\right)\times x=90\)

Ta có : 90 = 9 x 10

Vậy x = 9