Đặt A=1.2.3+2.3.4+...+2014.2015.2016
4A=1.2.3.4+2.3.4(-1+5)+...+2014.2015.2016(-2013+2017)
4A=1.2.3.4-1.2.3.4+2.3.4.5+...-2013.2014.2015.2016+2014.2015.2016.2017
rút hết còn 4A=2014.2015.2016.2017
A=2014.2015.2016.2017/4
tinh nhanh bieu thuc sau
a) x^6-20x^5-20x^4-20x^4-20x^3-20x^2-20x+1992 voi x= 21
b)x^7-26x^6+27x^5-47x^4-77x^3+50x^2+x+1989 tai x = 25
c)4029-2015x+2015x^2-....+2015x^2014-x^2015 tai x= 2014
d)A= (x-1/x-2015+x-2/x-2014+x-3/x-2013+....+x-2014/x-2+x-2015/x-1):(1/2 +1/3+1/4+....+1/2016) tai x=2016 dau / o day la phan do nha!!
xin nho cac ban giai giup cho minh! cam on nhieu!!!!!!!! minh dang can ket qua gap
Cho A= 1/2015 +2/2016+3/2017+...+2014/4028 -2014
B = 1/2015+1/2016+1/2017+...+1/4028.
Tính : A/B =?
tính (2016^2+2014^2+2012^2+......+4^2+2^2)-(2015^2+2013^2+2011^2+.....+3^2+1^2)
1) (8x-5)(x2+2014)=0
2) \(\frac{2-x}{2015}-1=\frac{1-x}{2016}\)\(-\frac{x}{2017}\)
3) \(\frac{x-1}{2016}+\frac{x-2}{2015}=\frac{x-3}{2014}\)\(+\frac{x-4}{2013}\)
4) (2x-5)3-(3x-4)3+(x+1)3=0
bài 2: Tính nhanh
a) A = 201^2
b) B= 498^2
c) C= 93. 107
d) D= 2016^2 - 2015. 2017
e) E= 2016^3 - 1
________
2016^2 + 2017
g) G= 2016^2 - 2015^2 + 2014^2 - 2013^2 + 2012^2 - 2011^2 + 2010^2 - 1^2
giúp tôi giải bài toán:(x+1)/2016)+(x+2)/2015)+(x+3)/2014)+(x+4)/2013)=0
\(\dfrac{x}{2012}\) +\(\dfrac{x+1}{2013}\)+\(\dfrac{x+2}{2014}\)+\(\dfrac{x+3}{2015}\)+\(\dfrac{x+4}{2016}\)=5
giải phương trình :
(x/2012)+(x+1/2013)+(x+2/2014)+(x+3/2015)+(x+4/2016)=5
\(\dfrac{x+1}{2012}+\dfrac{x+2}{2011}+\dfrac{x+3}{2010}=\dfrac{x-1}{2014}+\dfrac{x-2}{2015}+\dfrac{x-3}{2016}\)
