Tính nhanh:
2014 x 2016 + 2017 : 2015 x 2015 + 2016
Tinh nhanh phan so
2015 x 2017 - 1 / 2014 + 2015 x 2016
\(2015.2017-\frac{1}{2014}+2015.2016\)
\(=2015.\left(2017+2016\right)-\frac{1}{2014}\)
\(=2015.4033-\frac{1}{2014}\)
\(=8126495\)
Tinh nhanh co ma
Chua phai tinh nhanh dau
so sánh P và Q biết : P= 2014/2015 + 2015/2016 + 2016/2017 và Q = 2014 + 2015 +2016/ 2015 +2016 + 2017
1,Tính nhanh
[2015*2015*2014-2014-2014*2015]*[2016*2016+2015*2015*2016]
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
\(\frac{x+2014}{2015}+\frac{x+2015}{2016}=\frac{x+2016}{2017}+\frac{x+2017}{2018}\)
\(\Leftrightarrow\)\(\frac{x+2014}{2015}-1+\frac{x+2015}{2016}-1=\frac{x+2016}{2017}-1+\frac{x+2017}{2018}-1\)
\(\Leftrightarrow\)\(\frac{x-1}{2015}+\frac{x-1}{2016}=\frac{x-1}{2017}+\frac{x-1}{2018}\)
\(\Leftrightarrow\)\(\left(x-1\right)\left(\frac{1}{2015}+\frac{1}{2016}-\frac{1}{2017}-\frac{1}{2018}\right)=0\)
\(\Leftrightarrow\)\(x-1=0\) ( do 1/2015 + 1/2016 - 1/2017 - 1/2018 # 0 )
\(\Leftrightarrow\) \(x=1\)
Tìm x :
\(\frac{x=2015}{2016}+\frac{x+2016}{2015}+\frac{x+2017}{2014}=-3\)
\(\frac{x+2015}{2016}+\frac{x+2016}{2015}+\frac{x+2017}{2014}=-3\)
\(\Leftrightarrow\frac{x+2015}{2016}+1+\frac{x+2016}{2015}+1+\frac{x+2017}{2014}+1=0\)
\(\Leftrightarrow\frac{x+4031}{2016}+\frac{x+4031}{2015}+\frac{x+4031}{2014}=0\)
\(\Leftrightarrow\left(x+4031\right)\left(\frac{1}{2016}+\frac{1}{2015}+\frac{1}{2014}\right)=0\)
Có: \(\frac{1}{2016}+\frac{1}{2015}+\frac{1}{2014}\ne0\)
\(\Rightarrow x+4031=0\)
\(\Rightarrow x=-4031\)
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
tính nhanh:
(2^2016+2^2017+2^2018):(2^2014+2^2015+2^2016)
Ta có \(\left(2^{2016}+2^{2017}+2^{2018}\right):\left(2^{2014}+2^{2015}+2^{2016}\right)\)
\(=\left[2^{2016}.\left(1+2+2^2\right)\right]:\left[2^{2014}.\left(1+2+2^2\right)\right]\)
\(=2^{2016}.7:2^{1014}.7\)( cái này muốn tính dễ thì bạn để dạng phân số \(\frac{2^{2016}.7}{2^{2014}.7}=2^2\))
\(=2^2\)
\(=4\)
Tính nhanh : \(\frac{2017+\frac{1}{2016}+\frac{2}{2015}+\frac{3}{2014}+...+\frac{2015}{2}+\frac{2016}{1}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{2015}+\frac{1}{2016}}\)
Tính 2014 x 2015 + 2016 / 2016 x 2015 - 2014
\(\frac{2014.2015+2016}{2015.2016-2014}=\frac{2014.2015+2016}{2015.2014+4030-2014}=\frac{2014.2015+2016}{2014.2015+2016}=1\)