1 + 1 = 2

1 + 3 = 4

5 + 5 = 10

1+1=2

1+3=4

5+5=10

mk nhé 

kb nha

1+3=4

5+5=10

T I C K nha

    A = 8 - 8² + 8 + 8³ + 8⁴+ ......+ 8⁹⁹

        A = ( 8 - 8 ) + ( 8² + 8³ + 8⁴ +......+ 8⁹⁹ )

        A = 8² + 8³ + 8⁴ +......+ 8⁹⁹

       8A = 8³ + 8⁴ + 8⁵ +.......+ 8¹⁰⁰ 

  8A - A = ( 8³ + 8⁴ +...+ 8¹⁰⁰ ) - ( 8² + 8³ + ...+ 8⁹⁹ )

       7A = 8¹⁰⁰ - 8²

    => A = \(\frac{8^{100}-8^2}{7}\)

VẬY, \(A=\frac{8^{100}-8^2}{7}\)

37

k mik nha !

37 nha bạn

1 +1 +2 +3 +4 + 5+6+ 7+ 8 = 37

1+1=2

2+2=4

3+3=6

4+4=8

5+5=10

1+2+3+4+5+6+7+8+9+10=55

2

4

6

8

10

55

1+1=2 

2+2= 4 

3+3= 6  

4+4= 8 

5+5= 10 

1+2+3+4+5+6+7+8+9+10= 55 

kb nhé hok tốt

a) \(0,5x-\frac{2}{3}x=\frac{7}{12}\)

\(\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow x\left(\frac{1}{2}-\frac{2}{3}\right)=\frac{7}{12}\)

\(x.\frac{-1}{6}=\frac{7}{12}\)

\(x=\frac{7}{12}:\frac{-1}{6}\)

\(x=\frac{-7}{2}\)

b) \(x:4\frac{1}{3}=-2,5\)

\(x:\frac{13}{3}=\frac{-5}{2}\)

\(x=\frac{-5}{2}.\frac{13}{3}\)

\(x=\frac{-65}{6}\)

c) \(5,5x=\frac{13}{15}=\frac{11}{2}x=\frac{13}{5}\)

\(x=\frac{13}{5}:\frac{11}{2}\)

\(x=\frac{26}{55}\)

d) \(\left(\frac{3x}{7}+1\right):\left(-4\right)=\frac{-1}{28}\)

\(\frac{3x}{7}+1=\frac{-1}{28}.\left(-4\right)\)

\(\frac{3x}{7}+1=\frac{1}{7}\)

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

\(\frac{3x}{7}=\frac{-6}{7}\)

\(\frac{3x}{7}=\frac{-6}{7}\Rightarrow\frac{3.\left(-2\right)}{7}=\frac{-6}{7}\)

Vậy x = -2

\(0,5x-\frac{2}{3}x=\frac{7}{12}\)\(\)

\(\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)

\(x.\left(\frac{1}{2}-\frac{2}{3}\right)=\frac{7}{12}\)

\(x.\frac{-1}{6}=\frac{7}{12}\)

\(x=\frac{7}{12}:\frac{-1}{6}\)

\(x=3,5\)

mình cần gấp giúp mình với

số nào nhân 0 chả =0

HT

chúc bn năm mới vui vẻ

@@@@@@@@@@@@@@@@@@@

0 nha

T i c k mik nha

(1+2+3+4+5+..........+99999999999999999)x0=0

HT

@@@@@@@@@@@@@@@@@@

a) \(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+........+\frac{1}{99.100}\)

\(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+.........+\frac{1}{99}-\frac{1}{100}\)

\(=\frac{1}{2}-\frac{1}{100}=\frac{49}{100}\)

b) \(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+..........+\frac{2}{73.75}\)

\(=\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+.......+\frac{1}{73}-\frac{1}{75}\)

\(=\frac{1}{3}-\frac{1}{75}=\frac{8}{25}\)

c) \(\frac{4}{4.6}+\frac{4}{6.8}+\frac{4}{8.10}+..........+\frac{4}{64.66}\)

\(=2.\left(\frac{2}{4.6}+\frac{2}{6.8}+\frac{2}{8.10}+..........+\frac{2}{64.66}\right)\)

\(=2.\left(\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+\frac{1}{8}-\frac{1}{10}+.....+\frac{1}{64}-\frac{1}{66}\right)\)

\(=2.\left(\frac{1}{4}-\frac{1}{66}\right)=2.\frac{31}{132}=\frac{31}{66}\)

d) \(\frac{9}{5.8}+\frac{9}{8.11}+\frac{9}{11.14}+........+\frac{9}{497.500}\)

\(=3.\left(\frac{3}{5.8}+\frac{3}{8.11}+\frac{3}{11.14}+..........+\frac{3}{497.500}\right)\)

\(=3.\left(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-\frac{1}{14}+......+\frac{1}{497}-\frac{1}{500}\right)\)

\(=3.\left(\frac{1}{5}-\frac{1}{500}\right)=3.\frac{99}{500}=\frac{297}{500}\)

e) \(\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}+......+\frac{1}{93.95}\)

\(=\frac{1}{2}.\left(\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+........+\frac{2}{93.95}\right)\)

\(=\frac{1}{2}.\left(\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+........+\frac{1}{93}-\frac{1}{95}\right)\)

\(=\frac{1}{2}.\left(\frac{1}{5}-\frac{1}{95}\right)=\frac{1}{2}.\frac{18}{95}=\frac{9}{95}\)

g) \(\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+..........+\frac{1}{200.203}\)

\(=\frac{1}{3}.\left(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+........+\frac{3}{200.203}\right)\)

\(=\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+......+\frac{1}{200}-\frac{1}{203}\right)\)

\(=\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{203}\right)=\frac{1}{3}.\frac{201}{406}=\frac{67}{406}\)

bạn juventus ơi , bạn làm nốt cho mình mấy câu sau với