Tinh nhanh phan so
2015 x 2017 - 1 / 2014 + 2015 x 2016
Những câu hỏi liên quan
C= (1/2015+2015/2016)-(1/2017-2014/2015)-(2016/2017-1/2016)
Tinh C.
Giai dum minh voi
C=(1/2015+2015/2016)-(1/2017-2014/2015)(2016/2017-1/2016)
C= 1/2015+2015/20161/2016+2014/2015-2016/2017+1/2016
C=(1/2015+2014/2015)+(2015/2016+1/2016)-(1/2017+2016/2017)
C=1+1-1
C=1
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Tinh A= 2014/2015+2015/2016+2016/2017+2017/2014 hay so sanh A voi 4
=(2014/2014)+(2015+2015)+(2016/2016)+(2017+2017)
=1+1+1+1
=4
vậy A=4 (4=4)
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a, x+1/2013+x+1/2014+x+1/2015=x+1/2016+x+1/2017
b,x-1/2013+x-2/2014+x-3/2015=x-4/2016-2
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
x-1/2017 + x-2/2016 = x-3/2015 + x-4/2014
\(x-\dfrac{1}{2017}+x-\dfrac{2}{2016}=x-\dfrac{3}{2015}+x-\dfrac{4}{2014}\)
\(\Rightarrow x+x-x-x=-\dfrac{4}{2014}-\dfrac{3}{2015}+\dfrac{2}{2016}+\dfrac{1}{2017}\)
\(\Rightarrow0=-\dfrac{4}{2014}-\dfrac{3}{2015}+\dfrac{2}{2016}+\dfrac{1}{2017}\) (vô lí)
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\(\dfrac{x-1}{2017}+\dfrac{x-2}{2016}=\dfrac{x-3}{2015}+\dfrac{x-4}{2014}\Leftrightarrow\left(\dfrac{x-1}{2017}-1\right)+\left(\dfrac{x-2}{2016}-1\right)=\left(\dfrac{x-3}{2015}-1\right)+\left(\dfrac{x-4}{2014}-1\right)\Leftrightarrow\left(x-2018\right)\left(\dfrac{1}{2017}+\dfrac{1}{2016}-\dfrac{1}{2015}-\dfrac{1}{2014}\right)=0\Leftrightarrow x=2018\)
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Ta có: \(\dfrac{x-1}{2017}+\dfrac{x-2}{2016}=\dfrac{x-3}{2015}+\dfrac{x-4}{2014}\)
\(\Leftrightarrow\dfrac{x-2018}{2017}+\dfrac{x-2018}{2016}-\dfrac{x-2018}{2015}-\dfrac{x-2018}{2014}=0\)
\(\Leftrightarrow x-2018=0\)
hay x=2018
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Tìm x biết:
\(\frac{x+2014}{2015}+\frac{x+2015}{2016}=\frac{x+2016}{2017}+\frac{x+2017}{2018}\)
trừ mỗi vế cho 2 rồi tách -2 thành -1và -1
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\(\frac{x+2014}{2015}+\frac{x+2015}{2016}=\frac{x+2016}{2017}+\frac{x+2017}{2018}\)
\(\Leftrightarrow\)\(\frac{x+2014}{2015}-1+\frac{x+2015}{2016}-1=\frac{x+2016}{2017}-1+\frac{x+2017}{2018}-1\)
\(\Leftrightarrow\)\(\frac{x-1}{2015}+\frac{x-1}{2016}=\frac{x-1}{2017}+\frac{x-1}{2018}\)
\(\Leftrightarrow\)\(\left(x-1\right)\left(\frac{1}{2015}+\frac{1}{2016}-\frac{1}{2017}-\frac{1}{2018}\right)=0\)
\(\Leftrightarrow\)\(x-1=0\) ( do 1/2015 + 1/2016 - 1/2017 - 1/2018 # 0 )
\(\Leftrightarrow\) \(x=1\)
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Xem thêm câu trả lời
x+1/2013+x+1/2014+x+1/2015=x+1/2016+x+1/2017
Ta có : \(\frac{x+1}{2013}+\frac{x+1}{2014}+\frac{x+1}{2015}=\frac{x+1}{2016}+\frac{x+1}{2017}\)
\(\Rightarrow\) \(\frac{x+1}{2013}+\frac{x+1}{2014}+\frac{x+1}{2015}-\frac{x+1}{2016}-\frac{x+1}{2017}=0\)
\(\Rightarrow\) \(\left(x+1\right)\left(\frac{1}{2013}+\frac{1}{2014}+\frac{1}{2015}-\frac{1}{2016}-\frac{1}{2017}\right)=0\)
Vì \(\left(\frac{1}{2013}+\frac{1}{2014}+\frac{1}{2015}-\frac{1}{2016}-\frac{1}{2017}\right)\ne0\)
Nên : x + 1 = 0
Vậy x = -1
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Tính nhanh:
2014 x 2016 + 2017 : 2015 x 2015 + 2016
2014 x 2016 + \(\frac{2017}{2015}\)x 2015 + 2016
= 2014 x 2016 + 2017 + 2016 x 1
= 2016 x ( 2014 + 1 ) + 2017
= 2016 x 2015 + 2017
= 4064257
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(x+2014)(x+2015)(x+2016)(x+2017)