\(\frac{x}{5}=2\frac{1}{6}\times1\frac{1}{5}\)
Tìm số tự nhiên X biết \(1\frac{1}{5}\times1\frac{1}{6}\times1\frac{1}{7}\times...\times1\frac{1}{2014}\) =X
\(1\frac{1}{5}\)X \(1\frac{1}{6}\) X \(1\frac{1}{7}\) X \(...\)X \(1\frac{1}{2014}\) = x
x = \(\frac{6}{5}\) X \(\frac{7}{6}\) X \(\frac{8}{7}\) X \(...\)X \(\frac{2015}{2014}\)
x = \(\frac{6\cdot7\cdot8\cdot...\cdot2015}{5\cdot6\cdot7\cdot...2014}\)
x = \(\frac{2015}{5}\)
x = 403
6/5 × 7/6 × 8/7 × ... × 2015/2014 = x
2015/5 = x
x = 403
Vậy x = 403
Ủng hộ mk nha ♡_♥☆_★^_-
\(\Rightarrow x=\frac{6}{5}\times\frac{7}{6}\times\frac{8}{7}\times.......\times\frac{2015}{2014}\)
\(\Rightarrow x=\frac{6\times7\times8\times......\times2015}{5\times6\times7\times......\times2014}\)
\(\Rightarrow x=\frac{2015}{5}=403\)
\(1\frac{1}{3}\times1\frac{1}{4}\times1\frac{1}{5}\times1\frac{1}{6}\times1\frac{1}{7}\times1\frac{1}{8}\times1\frac{1}{9}\times1\frac{1}{10}\times1\frac{1}{11}\)
\(1\frac{1}{3}.1\frac{1}{4}.1\frac{1}{5}.1\frac{1}{6}.1\frac{1}{7}.1\frac{1}{8}.1\frac{1}{9}.1\frac{1}{10}.1\frac{1}{11}\)
\(=\frac{4}{3}.\frac{5}{4}.\frac{6}{5}.\frac{7}{6}.\frac{8}{7}.\frac{9}{8}.\frac{10}{9}.\frac{11}{10}.\frac{12}{11}\)
\(=\frac{12}{3}=4\)
Tính nhanh : \(\frac{1}{8}\div12,5\%+\left(\frac{1\times2\times3+6\times4\times2}{5\times3\times1+5\times15\times25}+\frac{1}{2}\div50\%\right)-\left(\frac{1}{16}\div6,25\%+\frac{3+2+1+2+4+6}{1+3+5+25+15+5}\right)-\frac{1}{4}\div25\%\)
\(\frac{1}{8}=12,5\%\) ; \(\frac{1}{16}=6,25\%\) ; \(\frac{1}{2}=50\%\) ; \(\frac{1}{4}=25\%\)
Thay vào trên mà tính.
= \(1+\left(\frac{3\left(1x2+2x4x2\right)}{3\left(5+5x3x25\right)}+1\right)-\left(1+\frac{18}{54}\right)-1\) = \(\frac{18}{380}-\frac{18}{54}\)
tìm x
\(4\frac{5}{9}:2\frac{5}{18}-7< x< \left(3\frac{1}{5}:3,2+4,5\times1\frac{31}{45}\right):\left(-21\frac{1}{2}\right)\)
Tính lần lượt 2 vế ta được:
-5 < x< -0,4
=> x = -4, -3, -2, -1, 0
Tính nhanh:
a) 12,5 x 40,7 + 59,3 x 12,5
b) 1,9 + 1,8 + 1,7 + 1,6 + 1,5 + 1,4 + 1,3 + 1,2 + 1,1
c) \(1\frac{1}{10}\times1\frac{1}{11}\times1\frac{1}{12}\times1\frac{1}{13}\times1\frac{1}{14}\times1\frac{1}{15}\times1\frac{1}{16}\)
a)
12,5 x 40,7 + 59,3 x12,5
= 12,5 x ( 40,7 + 59,3)
= 12,5 x 100
= 1250
a]
12,5 x 40,7 + 59,3 x 12,5
= 12,5 x [ 40,7 + 59,3]
= 12,5 x 100 = 125
b]
1,9 + 1,8 + 1,7 + 1,6 + 1,5 , 1,4 , 1,3 , 1,2 , 1,1
= [1,9 + 1,1 ] + [1,8 + 1,2 ] + [ 1,7 + 1,3 ] + [1,6 + 1,4 ] + 1,5
= [3 + 3 + 3 + 3 ]+ 1,5
= 12 + 1,5
=13,5
1,1 + 1,2 + 1,3 + 1,4 + 1,5 + 1,6 + 1,7 + 1,8 + 1,9
= (1,1 + 1,9) + (1,2 + 1,8) + (1,3 + 1,7) + (1,4 + 1,6) + 1,5
= 3 + 3 + 3 + 3 + 1,5
= 6 + 3 + 3 + 1,5
= 9 + 3 + 1,5
= 12 + 1,5
= 13,5
Tìm \(x\in Z\) : \(4\frac{5}{9}\div2\frac{5}{18}-7< x< \left(3\frac{1}{3}\div3,2+4,5\times1\frac{31}{45}\right)\div\left(-21\frac{1}{2}\right)\)
\(\Leftrightarrow-5< x< -\dfrac{1037}{1260}\)
=>\(x\in\left\{-4;-3;-2;-1\right\}\)
Tính :
\(a,3\frac{1}{2}+5\frac{1}{3}\)
\(b,4\frac{1}{4}-2\frac{2}{3}\)
\(c,7\frac{2}{9}\times1\frac{3}{5}\)
\(d,6\frac{1}{4}\div2\frac{1}{3}\)
haizzz bn cứ làm như thường là đc ròi, cần j phải hỏi
Tại cô giáo chưa dậy đến đã giao bài về nhà nên mình mới không biết làm !!!
Tính A=112×113×114....×112016×112017A=1\frac{1}{2}\times1\frac{1}{3}\times1\frac{1}{4}....\times1\frac{1}{2016}\times1\frac{1}{2017}A=121×131×141....×120161×120171
\(1\frac{1}{2}\times1\frac{1}{3}\times1\frac{1}{4}\times...\times1\frac{1}{2017}\)
Ta có : \(1\frac{1}{2}\times1\frac{1}{3}\times1\frac{1}{4}\times.....\times1\frac{1}{2017}\)
\(=\frac{3}{2}.\frac{4}{3}.\frac{5}{4}.....\frac{2018}{2017}\)
\(=\frac{2018}{2}=1009\)
\(1\frac{1}{2}\times1\frac{1}{3}\times1\frac{1}{4}\times....\times1\frac{1}{2017}\)
\(=\frac{3}{2}\times\frac{4}{3}\times\frac{5}{4}\times...\times\frac{2018}{2017}\)
\(=\frac{3\times4\times5\times.....\times2018}{2\times3\times4\times.....\times2017}\)
\(=\frac{2018}{2}=1009\)