\(\frac{3+5+7+.....+2013}{2+4+6+....+2012+x}\) =1
ai đúng mk tk !
1.
a) \(\text{(3x-5)6=(3x-5)4}\)
2.
a)\(\frac{2}{7}.\frac{2012}{2011}-\frac{2}{2011}.\frac{1}{7}_{ }+\frac{4}{7}\)
b) \(\left(\frac{3}{1.8}+\frac{3}{8.15}+\frac{3}{15.22}+...+\frac{3}{106.113}\right)-\left(\frac{25}{50,55}\frac{25}{55.60}\frac{25}{60.65}...\frac{25}{95.100}\right)\)
ai nhanh đúng mk tk
\(B=\frac{1-3}{1\cdot3}+\frac{2-4}{2\cdot4}+\frac{3-5}{3\cdot5}+\frac{4-6}{4\cdot6}+............+\frac{2011-2013}{2011.2013}+\frac{2012-2014}{2012\cdot2014}-\frac{2013+2014}{2013\cdot2014}\)
Tìm x biết
a) \(\frac{x+7}{2010}+\frac{x+6}{2011}=\frac{x+5}{2012}+\frac{x+4}{2013}\)
b) \(\frac{11}{x^2+7}+\frac{23}{x^2+19}=3-\frac{7}{y+3}\)
Tìm x biết
a) \(\frac{x+7}{2010}+\frac{x+6}{2011}=\frac{x+5}{2012}+\frac{x+4}{2013}\)
b) \(\frac{11}{x^2+7}+\frac{23}{x^2+19}=3-\frac{7}{y+3}\)
Ta có:
\(\frac{x+7}{2010}+\frac{x+6}{2011}=\frac{x+5}{2012}+\frac{x+4}{2013}\)
\(\Leftrightarrow\left(\frac{x+7}{2010}+1\right)+\left(\frac{x+6}{2011}+1\right)=\left(\frac{x+5}{2012}+1\right)+\left(\frac{x+4}{2013}+1\right)\)
\(\Leftrightarrow\frac{x+2017}{2010}+\frac{x+2017}{2011}=\frac{x+2017}{2012}+\frac{x+2017}{2013}\)
\(\Leftrightarrow\left(x+2017\right)\left(\frac{1}{2010}+\frac{1}{2011}\right)=\left(x+2017\right)\left(\frac{1}{2013}+\frac{1}{2014}\right)\)
Suy ra \(x+2017=0\)
Vậy \(x=-2017\)
b) Dễ tự làm nhé
1 + 2-3-4 + 5 + 6-7-8 + 9 +............. -2012 +2013 + 2014=?
Giúp mk nha mn. Mai mk hok roy.
=(0+1+2-3)+(-4+5+6-7)+(-8+9+10-11)+....+(-2010+2011+2012-2013)+2014
=0+0+0+...+0+2014=2014
giải phương trình:
a)\(\frac{x+1}{9}+\frac{x+2}{8}=\frac{x+3}{7}+\frac{x+4}{6}\)
b)\(\frac{x}{2012}+\frac{x+1}{2013}+\frac{x+2}{2014}+\frac{x+3}{2015}+\frac{x+4}{2016}=5\)
a) \(\frac{x+1}{9}+\frac{x+2}{8}=\frac{x+3}{7}+\frac{x+4}{6}\)
\(\Rightarrow\frac{x+1}{9}+1+\frac{x+2}{8}+1=\frac{x+3}{7}+1+\frac{x+4}{6}+1\)
\(\Rightarrow\frac{x+10}{9}+\frac{x+10}{8}=\frac{x+10}{7}+\frac{x+10}{6}\)
\(\Rightarrow\frac{x+10}{9}+\frac{x+10}{8}-\frac{x+10}{7}-\frac{x+10}{6}=0\)
\(\Rightarrow\left(x+10\right)\left(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\right)=0\)
Mà \(\left(\frac{1}{9}< \frac{1}{8}< \frac{1}{7}< \frac{1}{6}\right)\)nên \(\left(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\right)< 0\)
\(\Rightarrow x+10=0\Rightarrow x=-10\)
Vậy x = -10
b) \(\frac{x}{2012}+\frac{x+1}{2013}+\frac{x+2}{2014}+\frac{x+3}{2015}+\frac{x+4}{2016}=5\)
\(\Rightarrow\frac{x}{2012}-1+\frac{x+1}{2013}-1+\frac{x+2}{2014}-1\)
\(+\frac{x+3}{2015}-1+\frac{x+4}{2016}-1=0\)
\(\Rightarrow\frac{x-2012}{2012}+\frac{x-2012}{2013}+\frac{x-2012}{2014}\)\(+\frac{x-2012}{2015}+\frac{x-2012}{2016}=0\)
\(\Rightarrow\left(x-2012\right)\left(\frac{1}{2012}+\frac{1}{2013}+\frac{1}{2014}+\frac{1}{2015}+\frac{1}{2016}\right)=0\)
Mà \(\left(\frac{1}{2012}+\frac{1}{2013}+\frac{1}{2014}+\frac{1}{2015}+\frac{1}{2016}\right)>0\)nên x - 2012 = 0
Vậy x = 2012
a, (x+1)/9 +1 + (x+2)/8 = (x+3)/7 + 1 + (x+4)/6 + 1
<=> (x+10)/9 +(x+10)/8 = (x+10)/7 + (x+10)/6
<=> (x+10). (1/9 +1/8 - 1/7 -1/6) =0
vì 1/9 +1/8 -1/7 - 1/6 khác 0
=> x+10=0
=> x=-10
\(\frac{X+5}{2014}+\frac{X+6}{2013}+\frac{X+7}{2012}=-3\)
Từ \(\frac{x+5}{2014}+\frac{x+6}{2013}+\frac{x+7}{2012}=-3\)
\(\Leftrightarrow\left(\frac{x+5}{2014}+1\right)+\left(\frac{x+6}{2013}+1\right)+\left(\frac{x+7}{2012}+1\right)=0\)
\(\Leftrightarrow\frac{x+2019}{2014}+\frac{x+2019}{2013}+\frac{x+2019}{2012}=0\)
\(\Leftrightarrow\left(x+2019\right)\left(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}\right)=0\)
\(mà\) \(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}>0\)
nên : \(x+2019=0\Leftrightarrow x=-2019\)
Vậy : \(x=-2019\)
\(\frac{x+5}{2014}+\frac{x+6}{2013}+\frac{x+7}{2012}=-3\\ \frac{x+5}{2014}+\frac{x+6}{2013}+\frac{x+7}{2012}+3=0\\ \left(\frac{x+5}{2014}+1\right)+\left(\frac{x+6}{2013}+1\right)+\left(\frac{x+7}{2012}+1\right)=0\\ \frac{x+2019}{2014}+\frac{x+2019}{2013}+\frac{x+2019}{2012}=0\\ \left(x+2019\right)\left(\frac{1}{2014}+\frac{1}{2013}+\frac{1}{2012}\right)=0\\ \Rightarrow x+2019=0\\x=-2019 \)
Vậy x = -2019
Tìm x :
5/4/7 + ( x - 2 ) x 1/3 = 17/3/4
Giúp mk nha ! Ai giải đúng và chính xác thik mk tk cho 6 tk đều lên điểm
\(5\frac{4}{7}\) + ( x-2 ) x 1/3 = \(17\frac{3}{4}\)
39/7 + ( x- 2 ) x 1/3 = 71/4
( x -2 ) x 1/3 = 71/4 - 39/7
( x -2 ) x 1/3 = 341/28
x - 2 = 341/28 : 1/3
x -2 = 341/28 x 3
x -2 = 1023/28
x = 1023/28 + 2
x = 1079/28
P/s : số lớn tek!?
Cbht!!!!!
\(\frac{\frac{5}{4}}{7}+\left(x-2\right)\times\frac{1}{3}=\frac{\frac{17}{3}}{4}\)
\(\frac{35}{4}+\left(x-2\right)\times\frac{1}{3}=\frac{68}{3}\)
\(\frac{35}{4}+\left(x-2\right)=68\)
\(x-2=68-8,75\)
\(x-2=59,25\)
\(x=59,25+2\)
\(x=61,25\)
Tìm x :
5/4/7 + ( x - 2 ) x 1/3 = 17/3/4
Giúp mk nha ! Ai giải đúng và chính xác thik mk tk cho 6 tk đều lên điểm
5/4/7 + ( x - 2 ) x 1/ 3 = 17 / 3 / 4
35/4 + ( x - 2 ) x 1/3 = 68/3
( x -2 ) x 1/3 = 68/3 - 35/4
( x-2 ) x 1/3 = 167 / 12
x - 2 = 167 / 12 : 1/ 3
x -2 = 167 / 4
x = 167 / 4 + 2
x = 175/4 .
35/4+ (x-2)x1/3= 68/3
(x-2)x1/3 = 68/3 -35/4=167/12
x-2 = 167/12 : 1/3 =167/4
x = 167/4 +2=175/8