1^{999999999999999999999999999999999999999} =1x1x1x1x1x1x1x1x1x1x1x1x1x....x1=1

=1

Tk mk.

a)Xét tg AHE.  BHD  có:

góc E=D=90¤

ggóc AHE=BHD (2 góc đối đỉnh)

suy ra 2 t giác đồng dạng

8a: 24 quyển

8b: 36 quyển

#)Giải :

1 + 1 = 2

82 x 4 = 328

40 : 5 = 8

#)Chúc bn học tốt :D

1 + 1 = 2

82 * 4 = 328

40 : 5 = 8

Hok tốt 

^^

a, \(\frac{5}{7}.3x-\frac{8}{5}=\frac{9}{35}\)

=> \(\frac{15}{7}x=\frac{9}{35}+\frac{8}{5}\)=> \(\frac{15}{7}x=\frac{9}{35}+\frac{56}{35}\)

=> \(\frac{15}{7}x=\frac{65}{35}=\frac{13}{7}\)=> \(x=\frac{13}{7}:\frac{15}{7}=\frac{13}{15}\)

vậy \(x=\frac{13}{15}\)

b, \(\frac{2}{9}.5x+\frac{1}{2}-\frac{1}{18}=\frac{5}{36}\)

=> \(\frac{10}{9}x+\frac{1}{2}=\frac{5}{36}+\frac{1}{18}\)=\(\frac{5}{36}+\frac{2}{36}=\frac{7}{36}\)

=> \(\frac{10}{9}x=\frac{7}{36}-\frac{1}{2}\)=\(\frac{7}{36}-\frac{18}{36}\)=\(\frac{-11}{36}\)=> \(x=\frac{-11}{36}:\frac{10}{9}\)=\(\frac{-11}{36}.\frac{9}{10}\)=\(\frac{-11}{40}\)

vậy x=\(\frac{-11}{40}\)

a, ta có : \(\frac{5}{7}.\frac{3x-8}{5}=\frac{9}{35}\Leftrightarrow\frac{3x-8}{5}=\frac{9}{35}:\frac{5}{7}\Leftrightarrow\frac{3x-8}{5}=\frac{9}{35}.\frac{7}{5}\)

\(\Leftrightarrow\frac{3x-8}{5}=\frac{9}{5.5}\Leftrightarrow3x-8=\frac{9}{25}.5\Leftrightarrow3x-8=\frac{9.5}{25}\)

\(\Leftrightarrow3x-8=\frac{9}{5}\Leftrightarrow3x-8=\frac{9}{5}+8\Leftrightarrow3x=\frac{9+8.5}{5}\)

\(\Leftrightarrow3x=\frac{49}{5}\Leftrightarrow x=\frac{49}{5}:3\Leftrightarrow x=\frac{49}{5}.\frac{1}{3}=\frac{49}{15}\)

~ Vậy, ta tìm được \(x=\frac{49}{15}\)

b, Ta có : \(\frac{2}{9}.\frac{5x+1}{2}-\frac{1}{18}=\frac{5}{36}\Leftrightarrow\frac{2}{9}.\frac{5x+1}{2}=\frac{5}{36}+\frac{1}{18}\)

\(\Leftrightarrow\frac{2}{9}.\frac{5x+1}{2}=\frac{5+2.1}{36}\Leftrightarrow\frac{2}{9}.\frac{5x+1}{2}=\frac{7}{36}\)

\(\Leftrightarrow\frac{5x+1}{2}=\frac{7}{36}:\frac{2}{9}\Leftrightarrow\frac{5x+1}{2}=\frac{7}{36}.\frac{9}{2}\Leftrightarrow\frac{5x+1}{2}=\frac{7.9}{4.9.2}\)

\(\Leftrightarrow\frac{5x+1}{2}=\frac{7}{8}\Leftrightarrow5x+1=\frac{7}{8}.2\Leftrightarrow5x+1=\frac{7.2}{8}\)

\(\Leftrightarrow5x+1=\frac{7}{4}\Leftrightarrow5x=\frac{7}{4}-1\Leftrightarrow5x=\frac{7-1.4}{4}\)

\(\Leftrightarrow5x=\frac{3}{4}\Leftrightarrow x=\frac{3}{4}:5\Leftrightarrow x=\frac{3}{4}.\frac{1}{5}\Leftrightarrow x=\frac{3}{20}\)

~ Vậy, ta tìm được \(x=\frac{3}{20}\)

a) vì a<b

<=>-5a>-5b

mà 7>2

<=>7-5a>2-5b

b) vì m<n <=>2m<2n<=>2m-5<2n-5

\(A=\frac{1}{2}.\left(\frac{2}{2.4}+\frac{2}{4.6}+...+\frac{2}{2018.2020}\right)\)

\(A=\frac{1}{2}.\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...+\frac{1}{2018}-\frac{1}{2020}\right)\)

\(A=\frac{1}{2}.\left(\frac{1}{2}-\frac{1}{2020}\right)\)

\(A=\frac{1}{2}.\frac{1009}{2020}\)

\(A=\frac{1009}{4040}\)

A=1/2.4+1/4.6+1/6.8+...+1/2018.2020

  =1/2(1/2-1/4+1/4-1/6+...+1/2018-1/2020)

    =1/2(1/2-1/2020)

   =1/2.1009/2020

   =1009/4040