a) \(437\times136-437\times125\)

\(=437\times\left(136-125\right)\)

\(=437\times11\)

\(=4807\)

b) \(2009\times71+29\times2009\)

\(=2009\times\left(71+29\right)\)

\(=2009\times100\)

\(=200900\)

a) 437 x 136 - 437 x 125

= 437 x (136 - 125 )

= 437 x 11

=  4807

b) 2009 x 71 + 29 x 2009

= 2009 x ( 71 + 29 ) 

= 2009 x 100

= 200900

a) 437 x 136 - 437 x 125

  = 437 x (136 - 125)

  = 437 x 11

  = 4807

b) 2009 x 71 + 29 x 2009

   = 2009 x (71 + 29)

   =2009 x 100

   =200900

                                                  nhớ nha!

2008*2009>2228*2009-1

2008*2009=2009*2008

T ick nhanh đi

\(\frac{x-2009-2010}{2008}+\frac{x-2008-2010}{2009}+\frac{x-2008-2009}{2010}=3\)

\(\Leftrightarrow\frac{x-2008-2009-2010}{2008}+\frac{x-2008-2009-2010}{2009}+\frac{x-2008-2009-2010}{2010}=0\)

\(\Leftrightarrow\left(x-2008-2009-2010\right)\left(\frac{1}{2008}-\frac{1}{2009}-\frac{1}{2010}\right)=0\)

\(\Leftrightarrow x-6027=0\Leftrightarrow x=6027\)

Câu 18: B

Câu 19: C

thiếu dấu phép tính à bạn

2009 x 20082008 - 2008 x 20092009

= 2009 x 10001 x 2008 - 2008 x 10001 x 2009

=0

k mik nha!

chúc bn học giỏi!!!

\(\frac{2009x2008-1}{2007x2009+2008}=\frac{2009x2007+2009-1}{2009x2007+2008}=1.\)

vậy biểu thức trên =1

......................... hihi !

hinhnhu 10.056

\(\frac{15}{21}:x=\frac{3}{7}+\frac{2008}{2009}.\frac{2000}{2008}+\frac{9}{2008}.\frac{2008}{2009}\)

\(\frac{15}{21}:x=\frac{3}{7}+\frac{2000}{2009}+\frac{9}{2009}=\frac{3}{7}+\frac{2009}{2009}=\frac{10}{7}\)

\(x=\frac{15}{21}:\frac{10}{7}=\frac{15}{21}.\frac{7}{10}=\frac{1}{2}\)

x=0,5