1+1/3+1/6+1/10+...+2/x.(x+1)=3984/1993
tìm x
1+1/3+1/6+1/10+...+2/x(x+1)=3984/1993
Tìm x:
a: 1/45+1/55+1/66+.....+2/x*(x+1)=1/9
b:1+1/3+1/6+1/10+.....+1/x*(x+1):2=3984/1993
A= ( 6 : 3/5 - 1 1/6 x 6/7 ) : ( 4 1/5 x 10/11 + 5 2/11 )
B= ( 1 - 1/2 ) x ( 1- 1/4 ) x ... x ( 1 - 1/2003 ) x ( 1 - 1/2004 )
C= 5 9/10 : 3/2 - ( 2 1/3 x 4 1/2 - 2 x 2 1/3 ) : 7/4
Giúp mình nhanh nha! Mình sẽ thick người đó
tìm x, biết :
a) 1/( x+1 ).( x+2 ) + 1/( x+2 ).( x+3 ) + 1/( x+3 ).( x+4 ) + ... + 1/( x+1999).( x+2000) = 1/x+200 = 1/5
b) 2/( x+1 ).( x+3 ) + 3/( x+3 ) .( x+6 ) + 4/( x+6 ).( x+10 ) + ... + 10/( x+45 ).( x+55 ) + 1/ x+55 = 1/6
a) \(\dfrac{1}{2}+x=\dfrac{5}{6}\)
\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{2}=\dfrac{5}{6}-\dfrac{3}{6}=\dfrac{2}{6}=\dfrac{1}{3}\)
b) \(x+\dfrac{1}{4}=\dfrac{3}{4}\)
\(\Rightarrow x=\dfrac{3}{4}-\dfrac{1}{4}=\dfrac{2}{4}=\dfrac{1}{2}\)
c) \(x-\dfrac{1}{5}=\dfrac{3}{10}\)
\(\Rightarrow x=\dfrac{3}{10}+\dfrac{1}{5}=\dfrac{3}{10}+\dfrac{2}{10}=\dfrac{5}{10}=\dfrac{1}{2}\)
d) \(\dfrac{5}{6}-x=\dfrac{1}{3}\)
\(\Rightarrow x=\dfrac{5}{6}-\dfrac{1}{3}=\dfrac{5}{6}-\dfrac{2}{6}=\dfrac{3}{6}=\dfrac{1}{2}\)
e) \(\dfrac{3}{10}+x=\dfrac{1}{2}\)
\(\Rightarrow x=\dfrac{1}{2}-\dfrac{3}{10}=\dfrac{5}{10}-\dfrac{3}{10}=\dfrac{2}{10}=\dfrac{1}{5}\)
g) \(x+\dfrac{1}{4}=\dfrac{3}{8}\)
\(\Rightarrow x=\dfrac{3}{8}-\dfrac{1}{4}=\dfrac{3}{8}-\dfrac{2}{8}=\dfrac{1}{8}\)
a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13
b) ⇒x=34−14=24=12⇒x=34−14=24=12
c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12
d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12
e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15
g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18
Đọc tiếp
a) ⇒x=56−12=56−36=26=13⇒x=56−12=56−36=26=13
b) ⇒x=34−14=24=12⇒x=34−14=24=12
c) ⇒x=310+15=310+210=510=12⇒x=310+15=310+210=510=12
d) ⇒x=56−13=56−26=36=12⇒x=56−13=56−26=36=12
e) ⇒x=12−310=510−310=210=15⇒x=12−310=510−310=210=15
g) ⇒x=38−14=38−28=18⇒x=38−14=38−28=18
1/ x + 1/2 = -5/3 6/ x - 1/5 = 9/10
2/ 1/3 - x = 3/5 7/ x + 5/12 = 3/8
3/ 3-4 + x = 7/2 8/ x + 5/4 = 7/6
4/ x - 4/3 = -7/9 9/ x - 2/7 = 1/35
5/ x - -7/3 = 5/6 10/ x - 1/5 = -7/10
\(1,\\ x+\dfrac{1}{2}=-\dfrac{5}{3}\\ x=-\dfrac{5}{3}-\dfrac{1}{2}\\ x=-\dfrac{13}{6}\\ Vậyx=-\dfrac{13}{6}\)
\(2,\\ \dfrac{1}{3}-x=\dfrac{3}{5}\\ x=\dfrac{1}{3}-\dfrac{3}{5}\\ x=-\dfrac{4}{15}\\ Vậyx=-\dfrac{4}{15}\)
\(3,\\ 3-4+x=\dfrac{7}{2}\\ -1+x=\dfrac{7}{2}\\ x=\dfrac{7}{2}+1\\ x=\dfrac{9}{2}\\ Vậyx=\dfrac{9}{2}\)
\(4,\\ x-\dfrac{4}{3}=-\dfrac{7}{9}\\ x=-\dfrac{7}{9}+\dfrac{4}{3}\\ x=\dfrac{15}{27}\\ Vậyx=\dfrac{15}{27}\)
\(5,\\ x-\left(-\dfrac{7}{3}\right)=\dfrac{5}{6}\\ x=\dfrac{5}{6}-\dfrac{7}{3}\\ x=-\dfrac{27}{18}\\ Vậyx=-\dfrac{27}{18}\)
\(6,\\ x-\dfrac{1}{5}=\dfrac{9}{10}\\ x=\dfrac{9}{10}+\dfrac{1}{5}\\ x=\dfrac{11}{10}\\ Vậyx=\dfrac{11}{10}\)
\(7,\\ x+\dfrac{5}{12}=\dfrac{3}{8}\\ x=\dfrac{3}{8}-\dfrac{5}{12}\\ x=-\dfrac{1}{24}\\ Vậyx=-\dfrac{1}{24}\)
\(8,\\ x+\dfrac{5}{4}=\dfrac{7}{6}\\ x=\dfrac{7}{6}-\dfrac{5}{4}\\ x=-\dfrac{9}{24}\\ Vậyx=-\dfrac{9}{24}\)
\(9,\\ x-\dfrac{2}{7}=\dfrac{1}{35}\\ x=\dfrac{1}{35}+\dfrac{2}{7}\\ x=\dfrac{11}{35}\\ Vậyx=\dfrac{11}{35}\\ 10,\\ x-\dfrac{1}{5}=-\dfrac{7}{10}\\ x=-\dfrac{7}{10}+\dfrac{1}{5}\\ x=-\dfrac{1}{2}\\ Vậyx=-\dfrac{1}{2}\)
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3/5 + 2/5 : x = 1 1/10
( x - 3/5) x 3/8 - 5/8 = 1/6
1 1/6 - 5/6 : ( x+1/4) = 1/2
SOS
`3/5+2/5:x=1 1/10`
`3/5+2/5:x=11/10`
`2/5:x=11/10-3/5=1/2`
`x=2/5:1/2=4/5`
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`(x-3/5)xx3/8-5/8=1/6`
`(x-3/5)xx3/8=1/6+5/8`
`(x-3/5)xx3/8=4/24+15/24=19/24`
`x-3/5=19/24:3/8=19/9`
`x=19/9+3/5=122/45`
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`1 1/6-5/6:(x+1/4)=1/2`
`7/6-5/6:(x+1/4)=1/2`
`5/6:(x+1/4)=7/6-1/2=2/3`
`x+1/4=5/6:2/3=5/4`
`x=5/4-1/4=4/4=1`
tính:
1 + 3 + 6 + 10 +....+ 45 + 55/ 1 x 10 + 2 x 9 + 3 x 8 +...+ 8 x 3 + 9 x 2 + 10 x 1
1) 1/3 x 1/2 x 3/7 2) 5/4 x 1/3 + 1/7 3) 8 x ( 8/9-2/3 ) 4) 5/6 x 48/20 x 1/2 5) ( 2/5 + 3/4 ) x 8 6) 10 x ( 1/2-1/5 )
1) 1/3 x 1/2 x 3/7 = 1/6 x 3/7 = 1/14
2) 5/4 x 1/3 + 1/7 = 5/12 + 1/7 = 47/84
3) 8 x (8/9 - 2/3) = 8 x 2/9 = 16/9
4) 5/6 x 48/20 x 1/2 = 2 x 1/2 = 1
5) (2/5 + 3/4) x 8 = 23/20 x 8 = 46/5
6) 10 x (1/2 - 1/5) = 10 x 3/10 = 3