x+5/2005+x+4/2004+x+3/2003
I, Tìm x: a, \(\dfrac{x-2004}{2003}+\dfrac{x-2003}{2005}+\dfrac{x-2005}{2004}=3+\dfrac{2005}{2004}+\dfrac{2004}{2005}\)
x+2/2006+x+3/2005+x+1/2004+x+5/2003=x+4/503
Tìm x: a, \(\frac{x-2004}{2003}+\frac{x-2003}{2004}+\frac{x-2005}{2004}=3+\frac{2005}{2003}\)\(+\frac{2004}{2005}\)
c) 22/5 + 51/9 + 11/4 + 3/5 + 1/3 + 1/4
= 22/5 +3/5 +51/9 + 1/3 +11/4+1/4
= (22/5 +3/5) +(51/9 + 3/9) +(11/4+1/4)
= 25/5 +54/9 +12/4
= 5 +6 +3
= 14
d) (1/6 + 1/10 + 1/15) : (1/6 + 1/10 - 1/15)
= (5/30 + 3/30 +2/30 ) :(5/30 +3/30 -2/30)
= 10/30 : 6/30
= 1/3 : 1/5
= 5/3
Tìm x biết Ax + B = C
A = 158 x 12 - 12/7 - 12/289 -12/85 // 4 - 4/7 - 4/289 - 4/85 : 1/6 x 505505505 / 711711711 - 2005
B = 2003 x [2004 ^2003 + 2004^2002 + ..... + 2004 + 1] - 2004^2004 - 5
C= 2003 x 1986 + 2002 x 17 + 2020 / 2003 x 2004 - 2003 ^2
jup mik nhe
x+5/2005+x+6/2004+x+7/2003=-3
\(\dfrac{x+5}{2005}\)+\(\dfrac{x+6}{2004}\)+\(\dfrac{x+7}{2003}\)=-3
\(\dfrac{x+5}{2005}+\dfrac{x+6}{2004}+\dfrac{x+7}{2003}=-3\\ \Rightarrow\dfrac{x+5}{2005}+\dfrac{x+6}{2004}+\dfrac{x+7}{2003}+3=0\\ \Rightarrow\left(\dfrac{x+5}{2005}+1\right)+\left(\dfrac{x+6}{2004}+1\right)+\left(\dfrac{x+7}{2003}+1\right)=0\\ \Rightarrow\dfrac{x+2010}{2005}+\dfrac{x+2010}{2004}+\dfrac{x+2010}{2003}=0\\ \Rightarrow\left(x+2010\right)\left(\dfrac{1}{2005}+\dfrac{1}{2004}+\dfrac{1}{2003}\right)=0\\ \Rightarrow x+2010=0\left(\dfrac{1}{2005}+\dfrac{1}{2004}+\dfrac{1}{2003}\ne0\right)\\ \Rightarrow x=-2010\)
Tìm x : x+5/2005 + x+6/2004 + x+7/2003 = -3
\(\frac{x+5}{2005}+1+\frac{x+6}{2004}+1+\frac{x+7}{2003}+1=-3+3=0\)
\(\frac{x+2010}{2005}+\frac{x+2010}{2004}+\frac{x+2010}{2003}=0\)
\(\left(x+2010\right)\left(\frac{1}{2005}+\frac{1}{2004}+\frac{1}{2003}\right)=0\)
=> x + 2010 = 0
=> x = -2010
Tìm x : x+5/2005 + x+6/2004 + x+7/2003 = -3
\(\frac{x-5}{2000}+\frac{x-4}{2001}+\frac{x-3}{2002}=\frac{x-2}{2003}+\frac{x-1}{2004}+\frac{x}{2005}\)
Bạn chuyển về 1 vế sau đó trừ 1 vào mỗi phân thức ta được :
\(\left(x-2005\right)\left(\frac{1}{2000}+\frac{1}{2001}+\frac{1}{2002}-\frac{1}{2003}-\frac{1}{2004}-\frac{1}{2005}\right)=0\)
Vì biểu thức bên phải khác 0 nên : \(x-2005=0\)=> \(x=2005\)
\(\frac{x-5}{2000}+\frac{x-4}{2001}+\frac{x-3}{2002}=\frac{x-2}{2003}+\frac{x-1}{2004}+\frac{x}{2005}\)
\(\Leftrightarrow\frac{x-2005}{2000}+\frac{x-2005}{2001}+\frac{x-2005}{2002}=\frac{x-2005}{2003}+\frac{x-2005}{2004}+\frac{x-2005}{2005}\)
\(\Leftrightarrow\left(x-2005\right)\left(\frac{1}{2000}+\frac{1}{2001}+\frac{1}{2002}-\frac{1}{2003}-\frac{1}{2004}-\frac{1}{2005}\right)=0\)
<=> x - 2005 = 0
<=> x = 2005
Vậy ...............