Kết quả là:0

( 35 x 18 - 9 x 70 ) x 2010 x 2011 x ... x 2020

= (35 x 18 - 9 x 35 x 2) x 2010 x 2011 x ... x 2020

= ( 35 x 18 - 18 x 35 ) x 2010 x 2011 x ... x 2020

= 35 x (18 - 18 ) x 2010 x 2011 x ... x 2020

= 35 x 0 x 2010 x 2011 x ... x 2020 

= 0 x 2010 x 2011 x ... x 2020 

= 0

\(=9\times\left(70-70\right)+2020\)

\(=0+2020=2020\)

2020

=2020

2020

35 x 18 - 9 x 70 + 100 

= 70 x 9 - 9 x 70 + 100

=         0            + 100

=        100

35 x 18 - 9 x 70 + 100

= 35 x 2 x 9 - 9 x 70 + 100

= 70 x 9 - 9 x 70 + 100

= (70 - 70) x 9 + 100

= 0 x 9 + 100

= 100

\(a,-\frac{9}{12}=-\frac{9:3}{12:3}=-\frac{3}{4}\)

\(\frac{-18}{-24}=\frac{\left(-18\right):\left(-6\right)}{\left(-24\right):\left(-6\right)}=\frac{3}{4}\)

\(-\frac{35}{70}=-\frac{35:35}{70:35}=\frac{1}{2}\)

\(-\frac{9}{27}=-\frac{9:9}{27:9}=-\frac{1}{3}\)

\(b,\frac{1313}{4242}=\frac{1313:101}{4242:101}=\frac{13}{42}\)

\(\frac{-353535}{-424242}=\frac{\left(-353535\right):\left(-70707\right)}{\left(-424242\right):\left(-70707\right)}=\frac{5}{6}\)

\(c,\frac{2^3\times4^3\times5^4}{8^2\times25^3\times7}=\frac{2^3\times4^3\times25^2}{8\times8^2\times25^2\times25\times7}\)         ( 4^3 = 8^2 ; 5^4 = 25^2 )

\(=\frac{1}{25\times7}=\frac{1}{175}\)

\(a.\frac{-9}{-12}=\frac{-9:3}{-12:3}=\frac{-3}{-4}.\)

\(\frac{-18}{-24}=\frac{-18:6}{-24:6}=\frac{-3}{-4}\)

\(\frac{-35}{-70}=\frac{-35:35}{-70:35}=\frac{-1}{-2}\)

\(\frac{-9}{-27}=\frac{-9:9}{-27:9}=\frac{-1}{-3}\)

35 x 18 - 9 x 70 + 100

= 35 x 2 x 9 - 9 x 70 + 100

= 70 x 9 - 9 x 70 + 100

= 0 + 100

= 100

Tính nhanh : 

35 × 18 - 9 × 70 + 100

= 35 × ( 2 × 9 ) - 9 × 70 + 100

= 35 × 2 × 9 - 9 × 70 + 100

= ( 35 × 2 ) × 9 - 9 × 70 + 100

= 70 × 9 - 9 × 70 + 100

= 9 × ( 70 - 70 ) + 100

= 9 × 0 + 100

= 0 + 100

= 100

A<B chac luon

xét tổng quát (n-1)(n+1)=n(n+1)-(n+1)=n²+n-n-1=n²-1<n²=n.n

từ đó suy ra 2009.2011=(2010-1).(2010+1)=2010²-1<2010²=2010.2010

( 35 x 18 - 9 x 70 ) x 2010 x 2011 x 2012 x ... x 2020

= 0 x 2010 x 2011 x 2012 x ... x 2020

= 0 nha !

(35*18-9*70)*2010*2011*.....*2020

=(630-630)*2010*........*2020

=0*2010*.........*2020

=0

CHÚC BẠN HỌC TỐT!

TL

a)    5x + 20 = 110      

<=> x = 90 : 5 = 18

 b) x + 18 = - 13 

 <=> x = - 31

  c) 120 - x =  50   

   <=> x = 70     

 d) 10 - x = -29  

     <=>  x = 39

e) - x + 31 = 61

<=> x = -30

f) -85 - x = --70

<=> x = 15

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