Tính nhanh
2013 x 2012 - 1/2011 x 2013 + 2012
Tính nhanh : 2011 x 2012 + 2013 x 21 + 1991 / 2012 x 2013 - 2012 x 2012
\(\frac{2011\times2012+2013\times21+1991}{2012\times2013-2012\times2012}\)
\(=\frac{2011\times2012+2013\times\left(21+1991\right)}{2012\times2013-2012\times2012}\)
\(=\frac{2011\times2012+2013\times2012}{2012\times2013-2012\times2012}=\frac{2011}{2012}\)
Tính giá trị biểu thức :
2012 x 2011 + 2012 x 11 + 2000 / 2013 x 2011 - 2011 x 2012
đáp án 100% là 2024
Kết quả là 2024 nha bạn
tìm x,biet(1/2+1/3+.............+1/2012+1/2013).x=2012/1+2011/2+2010/3+......+2/2011+1/2012
Tìm x biết (1/2+1/3+...+1/2012+1/2013).x = 2012/1+2011/2+2010/3+...+2/2011+1/2012
(1/2+1/3+..................+1/2012=1/2013).x=2012/1+2011/2+...................+2/2011+1/2012
(1/2+1/3+..................+1/2012=1/2013).x=2012/1+2011/2+...................+2/2011+1/2012
(1/2+1/3+..................+1/2012=1/2013).x=2012/1+2011/2+...................+2/2011+1/2012
\(\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2012}+\frac{1}{2013}\right)x=\frac{2012}{1}+\frac{2011}{2}+...+\frac{2}{2011}+\frac{1}{2012}\)
\(\Rightarrow\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2012}+\frac{1}{2013}\right)x=\left(1+\frac{2011}{2}\right)+...+\left(1+\frac{2}{2011}\right)+\left(1+\frac{1}{2012}\right)+1\)
\(\Rightarrow\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2012}+\frac{1}{2013}\right)x=\frac{2013}{2}+...+\frac{2013}{2011}+\frac{2013}{2012}+\frac{2013}{2013}\)
\(\Rightarrow\left(\frac{1}{2}+\frac{1}{3}+...+\frac{1}{2012}+\frac{1}{2013}\right)x=2013\left(\frac{1}{2}+...+\frac{1}{2011}+\frac{1}{2012}+\frac{1}{2013}\right)\)
\(\Rightarrow x=2013\)
Vậy x = 2013
(1/2+1/3+..................+1/2012=1/2013).x=2012/1+2011/2+...................+2/2011+1/2012
tìm x biết (x+2014)/2011 + (x+2013)/2012 = (x+2012)/2013 + (x+2011)/2014