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Rồi bạn Nguyễn Thị Thanh Mai 

5,5 + \(\dfrac{3}{4}\) - 5 + \(\dfrac{1}{4}\)

(5,5 - 5) + (\(\dfrac{3}{4}\) + \(\dfrac{1}{4}\))

= 0,5  + 1

= 1,5 

\(\dfrac{5}{2}\) x  \(\dfrac{2}{3}\) + \(\dfrac{1}{4}\) : \(\dfrac{3}{2}\)

= \(\dfrac{5}{2}\) x \(\dfrac{2}{3}\) + \(\dfrac{1}{4}\) x \(\dfrac{2}{3}\)

=  (\(\dfrac{5}{2}\) + \(\dfrac{1}{4}\)) x \(\dfrac{2}{3}\)

= (\(\dfrac{10}{4}\) + \(\dfrac{1}{4}\)) x \(\dfrac{2}{3}\)

= \(\dfrac{11}{4}\) x \(\dfrac{2}{3}\)

= \(\dfrac{11}{6}\) 

Tính \(x\): 

  435  - [\(x\) + 16] = 425 : 17

  435 - [\(x\) + 16] = 25

          [\(x\) + 16] = 435 - 25

           \(x\) + 16 = 410

           \(x\)        = 410 - 16

          \(x\)         = 394

A = \(\dfrac{1}{2}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{12}\) + \(\dfrac{1}{20}\)+...+ \(\dfrac{1}{812}\) + \(\dfrac{1}{870}\)

A = \(\dfrac{1}{1.2}\) + \(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) + \(\dfrac{1}{4.5}\)+...+ \(\dfrac{1}{28\times29}\)+ \(\dfrac{1}{29\times30}\)

A = \(\dfrac{1}{1}\) - \(\dfrac{1}{2}\) + \(\dfrac{1}{2}\)  - \(\dfrac{1}{3}\) + \(\dfrac{1}{3}\) - \(\dfrac{1}{4}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{5}\) +...+\(\dfrac{1}{28}\)-\(\dfrac{1}{29}\)+ \(\dfrac{1}{29}\) - \(\dfrac{1}{30}\)

A = 1 - \(\dfrac{1}{30}\)

A = \(\dfrac{29}{30}\)

29/30 nha

Đề là gì ạ

Ta có:

3000+ab x 10+3=ab x 11+2970

3000+3=ab x(11-10)+2970

3003=ab+2970

=>ab=3003-2970=33

đúng tick mk nha

a, 234576 + 578957 + 47958 = 861491

b, 41235 + 24756 - 37968 =  28023

c, 324586 - 178395 + 24605 = 170796

\(\overline{3ab3}\) = \(\overline{ab}\) \(\times\) 11 + 2970

3003 + \(\overline{ab}\) \(\times\) 10 = \(\overline{ab}\) \(\times\) 11 + 2970 

             \(\overline{ab}\) \(\times\) 11 = 3003 +  \(\overline{ab}\) \(\times\) 10  -  2970 

             \(\overline{ab}\)  \(\times\) 11 =   33 + \(\overline{ab}\) \(\times\) 10

\(\overline{ab}\)  \(\times\) 11 - \(\overline{ab}\) \(\times\) 10 = 33

                  \(\overline{ab}\)         = 33