14^2 x 14^8 / 14^6
tính nhanh 5/14 x 2/9 + 5/14 + 5/14 x 7/9, 6/8 : 7/6 - 6/8 : 1/6
a: \(=\dfrac{5}{14}\left(\dfrac{2}{9}+\dfrac{7}{9}+1\right)=\dfrac{5}{14}\cdot2=\dfrac{5}{7}\)
b: \(=\dfrac{6}{8}\left(\dfrac{6}{7}-6\right)=\dfrac{6}{8}\cdot\dfrac{-36}{7}=\dfrac{-216}{56}=\dfrac{-27}{7}\)
2 phần ( x + 2 ). ( x + 4 ) + 4 phần ( x + 4 ) .( x + 8 ) + 6 phần( x + 8 ) .( x + 14 ) = x phần( x + 2 ) ( x + 14 ) với ( x ∉ { − 2 , − 4 , − 8 , − 14 } ) .
2. Tìm x biết:
a)2(x+2)(x+4)\dfrac{2}{\left(x+2\right)\left(x+4\right)} + 4(x+4)(x+8)\dfrac{4}{\left(x+4\right)\left(x+8\right)} + 6(x+8)(x+14)\dfrac{6}{\left(x+8\right)\left(x+14\right)} = x(x+2)(x+14)\dfrac{x}{\left(x+2\right)\left(x+14\right)}
b)x2023\dfrac{x}{2023} + x+12022\dfrac{x+1}{2022} x+22021\dfrac{x+2}{2021} +...+ x+20221\dfrac{x+2022}{1} + 2023 = 0.
Gíup mình giải 2 bài này với!
Cảm ơn các bạn rất nhiều!!!
Tìm x biết:
2/(x+2)(x+4)+ 4/(x+4)(x+8)+6/(x+8)(x+14)=x/(x+2)(x+14)
Tìm x: 2/(x+2)(x+4)+4/(x+4)(x+8)+6/(x+8)(x+14)=x/(x+2)(x+14)
\(\frac{2}{\left(x+2\right)\left(x+4\right)}+\frac{4}{\left(x+4\right)\left(x+8\right)}+\frac{6}{\left(x+8\right)\left(x+14\right)}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
<=>\(\frac{1}{x+2}-\frac{1}{x+4}+\frac{1}{x+4}-\frac{1}{x+8}+\frac{1}{x+8}-\frac{1}{x+14}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
<=>\(\frac{1}{x+2}-\frac{1}{x+14}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
<=>\(\frac{12}{\left(x+2\right)\left(x+14\right)}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
<=>x = 12
\(\frac{2}{\left(x+2\right)\left(x+4\right)}+\frac{4}{\left(x+4\right)\left(x+8\right)}+\frac{6}{\left(x+8\right)\left(x+14\right)}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
\(\Leftrightarrow\frac{1}{x+2}-\frac{1}{x+4}+\frac{1}{x+4}-\frac{1}{x+8}+\frac{1}{x+8}-\frac{1}{x+14}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
\(\Leftrightarrow\frac{1}{x+2}-\frac{1}{x+14}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
\(\Leftrightarrow\frac{12}{\left(x+2\right)\left(x+14\right)}=\frac{x}{\left(x+2\right)\left(x+14\right)}\)
\(\Leftrightarrow x=12\)
Vậy \(x=12\)
nè cấc bạn sao đó lại bằng 12 khi ko có cái gì để suy ra
tính nhanh: 2/(x+2)(x+4)+4/(x+4)(x+8)+6/(x+8)(x+14)=x/(x+2)(x+14)
mong được giúp đỡ
\(\dfrac{2}{(x + 2)(x + 4)}+\dfrac{4}{(x + 4)(x + 8)}+\dfrac{6}{(x + 8)(x + 14)}=\dfrac{x}{(x + 2)(x + 14)}\)
\(\dfrac{2}{(x + 2)(x + 4)}+\dfrac{4}{(x + 4)(x + 8)}+\dfrac{6}{(x + 8)(x + 14)}=\dfrac{x}{(x + 2)(x + 14)}\)
\(\Leftrightarrow\dfrac{1}{x+2}-\dfrac{1}{x+4}+\dfrac{1}{x+4}-\dfrac{1}{x+8}+\dfrac{1}{x+8}-\dfrac{1}{x+14}=\dfrac{x}{\left(x+2\right)\left(x+14\right)}\)
\(\Leftrightarrow\dfrac{x}{\left(x+2\right)\left(x+14\right)}=\dfrac{x+14-x-2}{\left(x+2\right)\left(x+14\right)}=\dfrac{12}{\left(x+2\right)\left(x+14\right)}\)
=>x=12
1/Tính :
a. A= 1/17+ 7/17.27 + 7/27.37 + .................... +7/1997.2007
b. B=-1/2007.2006 - 1/2005.2006 - 1/2005.2004 - .................... - 1/3.2 - 1/2.1
2/Tim x biết :
2/(x+2)(x+4) + 4/(x+4)(x+8) + 6/(x+8)(x+14) = x/(x+2)(x+14)
Với x không thuộc tập hợp {-2;-4;-6;-8;-14}
A = 7/7.17 + 7/17.27 + 7/27.37 + ............ +7/1997.2007
A=7/10 ( 10/7.17 + 10/17.27 + 10/27.37 + ................+10/1997.2007)
A= 7/10 ( 1/7 -1/17 + 1/17 - 1/27 + 1/27 - 1/37 +...............+ 1/1997 - 1/2007)
A= 7/10 (1/7 - 1/2007)
A= 7/10 . 2000/14049
A=200/2007
bây h mk có vc rùi tích đúng nha tối mk lm típ cho