![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{2011x2010-1}{2009x2011+2010}=\frac{2011x\left(2009+1\right)-1}{2009x2011+2010}\)
\(=\frac{2011x2009+2011-1}{2009x2011+2010}=\frac{2011x2009+2010}{2009x2011+2010}=1\)
![](https://rs.olm.vn/images/avt/0.png?1311)
2016x2015-1/2014x2016-2015
=2016x(2014+1)-1/2014x2016-2015
=2016x2014-2016x1-1/2014x2016-2015
=2016x2014-2016-1/2014x2016-2015
=2016x2014-2015/2014x2016-2015
=1
![](https://rs.olm.vn/images/avt/0.png?1311)
vì 1/1*2=1-1/2
1/2*3=1/2-1/3
.....................
1/2014*2015=1/2014-1/2015
=1-1/2+1/2-1/3+1/3-....+1/2014-1/2015
=1-1/2015
=2014/2115
\(\frac{1}{1x2}+\frac{1}{2x3}+\frac{1}{3x4}+....+\frac{1}{2014x2015}\)
=\(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{99}-\frac{1}{100}\)
=\(1-\frac{1}{100}\)
=\(\frac{99}{100}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có: \(\frac{2015.2016-2}{2014.2015+4028}=\frac{2015.2016-2}{2014.2015+2.2014}=\frac{\left(2015+2\right).\left(2016-2\right)}{2014.\left(2015+2\right)}=\frac{2017.2014}{2017.2014}=1\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 1 : Tính nhanh :
a) 19 . 64 + 76 .34
= 38 . 32 + 38 . 68
= 38 . (32 + 68)
= 38 .100
= 3800
b) 35 . 12 + 65 . 13
= 35 . 12 + 65 . (12 + 1)
= 35 . 12 + 65 . 12 + 65
= 12 . (35 + 65) + 65
= 1200 + 65
= 1265.
Bài 2 :
a)
A = 1998 . 1998
=1998 . 1996 + 1998 . 2
B = 1996 . 2000
=1998 . 1996 + 1996 . 2
Vì 1998 . 2 >1996 . 2
=>A > B
b)
A= 2000 . 2000
= 1990 . 2000 + 2000 . 10
B = 1990 . 2010
=1990 . 2000 + 1990 . 10
Vì 2000 . 10 > 1990 . 10
=>A > B
a,19.64+76.34 b,35.12+63.13
TẤT CẢ CÁC SỐ CỦA A ĐỀU LỚN HƠN MỌI SỐ CỦA B NÊN A>B
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{2319}{2010}-\frac{1789}{2000}-\frac{309}{2010}+\frac{2009}{2010}-\frac{211}{2000}\)
\(=\left(\frac{2319}{2010}-\frac{309}{2010}+\frac{2009}{2010}\right)-\left(\frac{1789}{2000}-\frac{211}{2000}\right)\)
\(=\frac{4019}{2010}-\frac{789}{1000}\)
=))
![](https://rs.olm.vn/images/avt/0.png?1311)
(-376)+|-2010|-|-2000|-(-486)
=(-376)+2010-2000+486
= (-376)+2010+(-2000)+486
=[(-376)+486]+[2010+(-2000)]
= 110 + 10
= 120
(-376) + |-2010| - |-2000| - (-486)
= (-376) + 2010 - 2000 + 486
= [ (-376) + 486 ] + ( 2010 - 2000 )
= 110 + 10
= 120
![](https://rs.olm.vn/images/avt/0.png?1311)
\(t=\frac{2009.2010+2000}{2011.2010-2020}\)
\(t=\frac{2009.2010+2000}{\left(2009+2\right).2010-2020}\)
\(t=\frac{2009.2010+2000}{2009.2010+2.2010-2020}\)
\(t=\frac{2009.2010+2000}{2009.2010+2000}=1\)
\(q=\frac{\text{2014.2015+2010}}{2016.2015-2020}\)
\(q=\frac{\text{2014.2015+2010}}{\left(2014+2\right).2015-2020}\)
\(q=\frac{\text{2014.2015+2010}}{2014.2015+2.2015-2020}\)
\(q=\frac{\text{2014.2015+2010}}{\text{2014.2015+2010}}=1\)