\(B=\left(1-\frac{1}{2010}\right)x\left(1-\frac{2}{2010}\right)x\left(1-\frac{3}{2010}\right)x...x\left(1-\frac{2011}{2010}\right)\)

\(B=\left(1-\frac{1}{2010}\right)x\left(1-\frac{2}{2010}\right)x\left(1-\frac{3}{2010}\right)x....x\left(1-\frac{2010}{2010}\right)x\left(1-\frac{2011}{2010}\right)\)

\(B=\left(1-\frac{1}{2010}\right)x\left(1-\frac{2}{2010}\right)x\left(1-\frac{3}{2010}\right)x...x\left(0\right)x\left(1-\frac{2011}{2010}\right)\)

\(B=0\)

Phúc 6A phải k

`(2011xx2020-1)/(2009xx2011+2010)`

`=((2009+1)xx2011-1)/(2009xx2011+2010)`

`=(2009xx2011+2011-1)/(2009xx2011+2010)`

`=(2009xx2011+2010)/(2009xx2011+2010)`

`=1`

\(\dfrac{2011.2010-1}{2009.2011+2010}\) 

= \(\dfrac{2011.2009+2011-1}{2009.2011+2010}\) 

= \(\dfrac{2011.2009+2010}{2009.2011+2010}\) 

= 1

Bài 1 :

7^2x+3 . 7^5-2x : 7^x + 7^x = 1

- > 7^{(2x+3)+(5-2x)-7} + 7^x = 1

- > 7¹ + 7^x = 1

- > 7^x = 1 - 7 = -6 - > x thuộc rỗng

tính :

a)\(\frac{459}{987}\cdot\left(\frac{1}{4}+\frac{1}{12}-\frac{1}{3}\right)-\frac{2009}{2010}\)

\(=\frac{459}{987}\cdot\left(\frac{3}{12}+\frac{1}{12}-\frac{4}{12}\right)-\frac{2009}{2010}\)

\(=\frac{459}{987}\cdot0-\frac{2009}{2010}\)

\(=\frac{-2009}{2010}\)

b) \(\frac{-9}{7}-\frac{5}{7}\cdot\left[\left(\frac{-2}{3}\right)^2-1\right]\div\frac{-5}{9}\)

\(=\frac{-9}{7}-\frac{5}{7}\cdot\left[\frac{4}{9}-1\right]\div\frac{-5}{9}\)

\(=\frac{-9}{7}-\frac{5}{7}\cdot\frac{-5}{9}\div\frac{-5}{9}\)

\(=\frac{-9}{7}-\frac{5}{7}\)

\(=-2\)

tìm x:

a) \(\left(x-\frac{7}{18}\right)-\frac{15}{27}=\frac{-10}{27}\)

\(\left(x-\frac{7}{18}\right)=\frac{-10}{27}+\frac{15}{27}\)

\(\left(x-\frac{7}{18}\right)=\frac{5}{27}\)

\(x=\frac{5}{27}+\frac{7}{18}\)

\(\Rightarrow x=\frac{31}{54}\)

b) \(\left(3\frac{1}{2}-2x\right)\cdot\frac{11}{3}=7\frac{1}{3}\)

\(\left(\frac{7}{2}-2x\right)\cdot\frac{11}{3}=\frac{22}{3}\)

\(\left(\frac{7}{2}-2x\right)=\frac{22}{3}\div\frac{11}{3}\)

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

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

\(x=\frac{3}{2}\div2=\frac{3}{4}\)

\(\Rightarrow x=\frac{3}{4}\)

(2008 x 2009 x 2010 x 2011) x (1 + 1/2 : 3/2 - 4/3)

=(2008 x 2009 x 2010 x 2011) x (1 + 1/3 - 4/3)

=(2008 x 2009 x 2010 x 2011) x (4/3 - 4/3)

=(2008 x 2009 x 2010 x 2011) x 0

=0

đáp số:0

ủng hộ nha