\(=33333333^2\)NHA BẠN

A = 33333333²

A = 99999999

# Hok tốt !

cccccc

?????????

11111111

11111111

33333333+6456546556=6489879889

1111111

111111+2222222+33333333+44444444=80111110

80111110

Để:

1111111*33333333 chia hết cho 7 thì:

⇒ 11111111*3333333 + (3 x 5) phải chia hết cho 7

⇒ 11111111+* x 100000000 + 33333333 + 15 chia hết cho 7 

⇒ 44444459 + * x 100000000 chia hết cho 7 

⇒ * = 2 

* = 2

Đặt \(x\) là số cần tìm ta được : \(A=\overline{11111111x33333333}\)

\(\)Ta làm phép tính sau :

\(1.3=3\rightarrow3+1=4.3=12\rightarrow12+1=13.4=52\rightarrow52+1=53.3=159\rightarrow159+1=160.3=480\rightarrow480+1=481.3=1443\rightarrow1443+1=1444.3=4332\rightarrow4332+1=4333.3=12999\)

\(\left(12999+x\right).3=3x+38997\)

\(3x+38997+3=3x+3900\rightarrow\left(3x+3900\right).3=9x+11700\)

\(9x+11700+3=9x+11703\rightarrow\left(9x+11703\right).3=27x+35109\)

\(27x+35109+3=27x+35112\rightarrow\left(27x+35112\right).3=81x+105336\rightarrow\left(81x+105336\right).3=243x+316017\)

\(243x+316017+3=243x+316020\rightarrow\left(243x+316020\right).3=729x+948060\)

\(729x+948060+3=729x+948063\rightarrow\left(729x+948063\right).3=2187x+\text{2844189}\)

\(2187x+2844192+3=2187x+2844192\rightarrow\left(2187x+2844192\right).3=6561x+8532576\)

\(6561x+8532576+3=6561x+8532579\rightarrow\left(6561x+8532579\right).3=19683x+25597737\)

\(19683x+25597737+3=19683x+25597740\)

Để \(A⋮7\Leftrightarrow19683x+25597740⋮7\)

 mà \(25597740=3656820.7⋮7\)

       \(19683\) \(⋮̸\) \(7\)

\(\Rightarrow x=7\)

Vậy \(x=7\) thỏa yêu cầu đề bài

\(\frac{7}{4}\left(\frac{33}{12}+\frac{3333}{2020}+\frac{333333}{303030}+\frac{33333333}{42424242}\right)\)

=\(\frac{7}{4}\left(\frac{33}{12}+\frac{33}{20}+\frac{33}{30}+\frac{33}{42}\right)\)

=\(\frac{7}{4}.33\left(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}\right)\)

=\(\frac{231}{4}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\right)\)

=\(\frac{231}{4}\left(\frac{1}{3}-\frac{1}{7}\right)\)

=\(\frac{231}{4}.\frac{4}{21}\)

= 11

\(\dfrac{-7}{4}.\left(\dfrac{33}{12}+\dfrac{3333}{2020}+\dfrac{333333}{303030}+\dfrac{33333333}{42424242}\right)\)

\(=\dfrac{-7}{4}.\left(\dfrac{33}{12}.\dfrac{33.101}{20.101}.\dfrac{33.10101}{30.10101}.\dfrac{33.1010101}{42.1010101}\right)\)

\(=\dfrac{-7}{4}.\left(\dfrac{33}{12}.\dfrac{33}{20}.\dfrac{33}{30}.\dfrac{33}{42}\right)\)

\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+\dfrac{1}{42}\right)\)

\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}\right)\)

\(=\dfrac{-7}{4}.33.\left(\dfrac{1}{3}-\dfrac{1}{7}\right)\)

\(=\dfrac{-7}{4}.33.\dfrac{4}{21}\)

\(=33.\dfrac{-1}{3}\)

\(=11\)

xl nhé kết quả là -11 mk viết thiếu dấu -

Bằng 33333339

33333333 + ( 12 : 2 )

= 33333333 + 6

= 33333339

Tk mk nha !! n_n

Thanks ạ !! ^^

=333333339