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\(\left(1-\frac{1}{3}\right)x\left(1-\frac{1}{4}\right)x...x\left(1-\frac{1}{2014}\right)\)
A = \(\frac{2}{3}x\frac{3}{4}x\frac{4}{5}x...x\frac{2012}{2013}x\frac{2013}{2014}\)
A = \(\frac{2x3x4x...x2012x2013}{3x4x5x...x2013x2014}\)
a = \(\frac{2}{2014}=\frac{1}{1007}\)
a) (1,5 . 1,9 - x - 0,5) : 0,25 = 7,5 : 0,125
=> (2,85 - x - 0,5) : 0,25 = 60
=> (2,85 - 0,5) - x = 60 . 0,25
=> 2,35 - x = 15
=> x = 2,35 - 15
=> x = -12,65
Vậy x = -12,65
b) \(1-\left(5\frac{2}{9}+x-7\frac{7}{18}\right)\div2\frac{1}{6}=0\)
\(\Rightarrow\left(5\frac{2}{9}-7\frac{7}{18}+x\right)\div2\frac{1}{6}=1-0\)
\(\Rightarrow\left(\frac{47}{9}-\frac{133}{18}+x\right)\div2\frac{1}{6}=1\)
\(\Rightarrow\frac{-13}{6}+x=2\frac{1}{6}\)
\(\Rightarrow x=2\frac{1}{6}-\frac{-13}{6}\)
\(\Rightarrow x=\frac{13}{6}+\frac{13}{6}\)
\(\Rightarrow x=\frac{26}{6}\)
\(\Rightarrow x=\frac{13}{3}\)
Vậy \(x=\frac{13}{3}\)
c) \(35\left(2\frac{1}{5}-x\right)=32\)
\(\Rightarrow2\frac{1}{5}-x=32\div35\)
\(\Rightarrow\frac{11}{5}-x=\frac{32}{35}\)
\(\Rightarrow x=\frac{11}{5}-\frac{32}{35}\)
\(\Rightarrow x=\frac{9}{7}\)
Vậy \(x=\frac{9}{7}\)
d) \(\frac{4}{3}+\left(x\div2\frac{2}{3}-0,5\right).1\frac{35}{55}=0,6\)
\(\Rightarrow\left(x\div\frac{8}{3}-\frac{1}{2}\right).\frac{18}{11}=\frac{3}{5}-\frac{4}{3}\)
\(\Rightarrow\left(x\div\frac{8}{3}-\frac{1}{2}\right).\frac{18}{11}=\frac{-11}{15}\)
\(\Rightarrow x\div\frac{8}{3}-\frac{1}{2}=\frac{-11}{15}\div\frac{18}{11}\)
\(\Rightarrow x\div\frac{8}{3}-\frac{1}{2}=\frac{-121}{270}\)
\(\Rightarrow x\div\frac{8}{3}=\frac{-121}{270}+\frac{1}{2}\)
\(\Rightarrow x\div\frac{8}{3}=\frac{7}{135}\)
\(\Rightarrow x=\frac{7}{135}.\frac{8}{3}\)
\(\Rightarrow x=\frac{56}{405}\)
Vậy \(x=\frac{56}{405}\)
e) \(1\frac{1}{3}.2\frac{2}{4}\div\frac{5}{6}.1\frac{1}{11}=11-5\div x\)
\(\Rightarrow\frac{4}{3}.\frac{5}{2}\div\frac{5}{6}.\frac{12}{11}=11-5\div x\)
\(\Rightarrow\frac{10}{3}\div\frac{5}{6}.\frac{12}{11}=11-5\div x\)
\(\Rightarrow4.\frac{12}{11}=11-5\div x\)
\(\Rightarrow11-5\div x=\frac{48}{11}\)
\(\Rightarrow5\div x=11-\frac{48}{11}\)
\(\Rightarrow5\div x=\frac{73}{11}\)
\(\Rightarrow x=5\div\frac{73}{11}\)
\(\Rightarrow x=\frac{55}{73}\)
Vậy \(x=\frac{55}{73}\)
a) (1,5 * 1,9 - x - 0,5) : 0,25 = 7,5 : 0,125
(2,85 - x - 0,5) : 0,25 = 60
(2,85 - x - 0,5) = 60 x 0,25
(2,85 - x - 0,5) = 15
2,35 - x = 15
x = 2,35 - 15
x = -12,65
Bài 2: ta có tích riêng thứ nhất là .....5, thứ hai cũng là ....5 -> chữ số tận cùng là: ....5 - ....5 = ...0
Bài 3: Gọi số có hai chữ số đó là ab (a,b =<9)
...........................__..... _
Theo đề bài ta có: ab = 9b
=> b = (2; 3; 4; 5; 6; 7; 8; 9)
..........................................
=> Tương ứng với b ta có ab = (18; 27; 36; 45; 54; 63; 72; 81)
Nhận xét: Chỉ có 45 = 9.5
Vậy số đó là 45
a) 234 x 95 + 234 x 4 + 234 = 234 x ( 95 + 4 + 1 ) = 234 x 100 = 23400
a).234 x 95 + 234 x 4 + 234
= 234 x ( 95 + 4 + 1 )
= 234 x 100
= 23400
b) ( 1+1/2) x ( 1+1/3) x ( 1+1/4 )
= ( 2/2+1/2 ) x ( 3/3+1/3 ) x ( 4/4 + 1/4)
=3/2 + 4/3 + 5/4
= 18/12 + 16/12 + 20/12
= 54/12
= 9 /2
\(1-\left(11\frac{1}{2}-10,1+x\right):8\frac{2}{5}=0\)
=>\(1-\left(\frac{21}{2}-\frac{101}{10}+x\right):\frac{42}{5}=0\)
=> \(1-\left(\frac{2}{5}+x\right)=0\)
=>\(1=\frac{2}{5}+x\)
=>\(x=1-\frac{2}{5}\)
=>\(x=\frac{3}{5}\)
Vậy ..................
a, \(\frac{6+x}{33}=\frac{7}{11}\)
\(\Leftrightarrow\left(6+x\right).11=7.33\)
\(\Leftrightarrow66+11x=231\)
\(\Leftrightarrow11x=231-66\)
\(\Leftrightarrow x=\frac{165}{11}=15\)
Vậy x = 15.
b,\(\frac{12+x}{43-x}=\frac{2}{3}\)
\(\Leftrightarrow3.\left(12+x\right)=2\left(43-x\right)\)
\(\Leftrightarrow36+3x=86-2x\)
\(\Leftrightarrow3x+2x=-36+86\)
\(\Leftrightarrow5x=50\)
\(\Leftrightarrow x=10\)
Vây x = 10.
a, \(\frac{4}{5}-\frac{1}{3}x=\frac{1}{2}\Rightarrow\frac{1}{3}x=\frac{4}{5}-\frac{1}{2}=\frac{3}{10}\)
\(x=\frac{3}{10}.3=\frac{9}{10}\)
Vậy, \(x=\frac{9}{10}\)
b, \(2014:x=26\left(r=12\right)\) (r là số dư nhé bạn)
Vì \(2014:x=26\) dư \(12\Rightarrow\left(2014-12\right)⋮26\)
\(\Rightarrow2002:x=26\Rightarrow x=\frac{2002}{26}=77\)
Vậy, \(x=77\)
a) 4/5 - 1/3 x X = 1/2
=> 1/3 x X = 4/5 - 1/2
=> 1/3 x X = 3/10
=> X = 3/10 : 3
=> X = 9/10