= ( 1 + 3 + 5+ 7 + ... + 999 ).( 32 . 4 . 111  - 111 . 128)

= ( 1 + 3 + 5 + 7 + .. + 999 ). ( 128 . 111 - 111 . 128)

= ( 1 + 3 + 5 + .. + 999) . 0 

= 0 

2+2+19+x+5=30

=> 2+2+19+5+x=30

=> 28+x=30

=> x = 30-28

=> x = 2 

\(\left(\frac{3}{20}+\frac{1}{20}-x\right):\frac{32}{9}=\frac{21}{128}\)

\(\Leftrightarrow\frac{4}{20}-x=\frac{21}{128}.\frac{32}{9}\)

\(\Leftrightarrow\frac{1}{5}-x=\frac{7}{12}\)

\(\Leftrightarrow x=\frac{1}{5}-\frac{7}{12}\)

\(\Leftrightarrow x=-\frac{23}{60}\)

Vậy \(x=\frac{-23}{60}\)

Bài làm

\(\left(\frac{3}{20}+\frac{1}{20}-x\right):\frac{32}{9}=\frac{21}{128}\)

\(\left(\frac{3}{20}+\frac{1}{20}-x\right)=\frac{21}{128}.\frac{32}{9}\)

\(\frac{4}{20}-x=\frac{7}{4}.\frac{1}{3}\)

\(\frac{4}{20}-x=\frac{7}{12}\)

\(x=\frac{4}{20}-\frac{7}{12}\)

\(x=\frac{12}{60}-\frac{35}{60}\)

\(x=-\frac{23}{60}\)

Vậy \(x=-\frac{23}{60}\)

\(x=-\frac{37}{15}\)

\(\left(\frac{3}{20}+\frac{1}{2}-x\right):\frac{32}{9}=\frac{21}{128}\)

\(\left(\frac{13}{20}-x\right):\frac{32}{9}=\frac{21}{128}\)

\(\frac{13}{20}-x=\frac{21}{128}\times\frac{32}{9}\)

\(\frac{13}{20}-x=\frac{7}{12}\)

\(x=\frac{13}{20}-\frac{7}{12}\)

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

( 3/20 + 1/2 - x ) : 32/9 = 21/128

3/20+ 1/2 - x = 21/128 x 32/9

13/20 - x = 7/12

x = 13/20 - 7/12

x = 1/15

a) x-123=984

   x=984+123 

   x=1107

b) x+123:2=999

   x=999-(123:2)

   x=937,5 

a)1107

b)937,5

a.1081,2

b.1225

c.246,1

d.31227,125

e.965

g.2,05

sưả g=2,125