Tìm X:
\(\frac{2}{X}\)= \(\frac{5}{6}\)
Tìm x, biết x \(\in\)Z:
\(\frac{-5}{6}+\frac{8}{3}+\frac{29}{-6}\le x\le\)\(\frac{-1}{2}+2+\frac{5}{12}\)
Giải:
Theo bài ra ta có:
\(\frac{-5}{6}+\frac{8}{3}+\frac{29}{-6}\le x\le\frac{-1}{2}+2+\frac{5}{12}\)
\(\Rightarrow-3\le x\le\frac{23}{12}\)
\(\Rightarrow x\varepsilon\left\{-2;-1;0;1\right\}\)
\(\frac{-5}{6}+\frac{16}{6}+-\frac{29}{6}\le x\le\frac{-6}{12}+\frac{24}{12}+\frac{5}{12}\)
=>-3\(\le\) x\(\le\) 23/12
=> x thuộc{-2-1;0;1}
Tìm x biết
\(\frac{x-1}{117}+\frac{x-2}{118}+\frac{x-3}{119}=\frac{x-4}{120}+\frac{x-5}{121}+\frac{x-6}{122}\)
mình cần gấp
\(\Leftrightarrow\frac{x-1}{117}+1+\frac{x-2}{118}+1+\frac{x-3}{119}=\frac{x-4}{120}+1+\frac{x-5}{121}+1+\frac{x-6}{122}+1\)
\(\Leftrightarrow\frac{x+116}{117}+\frac{x+116}{118}+\frac{x+116}{119}-\frac{x+116}{120}-\frac{x+116}{121}-\frac{x+116}{122}=0\)
\(\Leftrightarrow\left(x+116\right)\left(\frac{1}{117}+\frac{1}{118}+\frac{1}{119}-\frac{1}{120}-\frac{1}{121}-\frac{1}{122}\right)=0\)
\(\Leftrightarrow x+116=0\Leftrightarrow x=-116\)
\(\frac{x-1}{117}+\frac{x-2}{118}+\frac{x-3}{119}=\frac{x-4}{120}+\frac{x-5}{121}+\frac{x-6}{122}\)
\(\Leftrightarrow\frac{x-1}{117}+1+\frac{x-2}{118}+1+\frac{x-3}{119}+1=\frac{x-4}{120}+1+\frac{x-5}{121}+1+\frac{x-6}{122}+1\)
\(\Leftrightarrow\frac{x+116}{117}+\frac{x+116}{118}+\frac{x+116}{119}-\frac{x+116}{120}-\frac{x+116}{121}-\frac{x+116}{122}=0\)
\(\Leftrightarrow\left(x+116\right)\left(\frac{1}{117}+\frac{1}{118}+\frac{1}{119}-\frac{1}{120}-\frac{1}{121}-\frac{1}{122}\right)=0\)
Vì \(\frac{1}{117}+\frac{1}{118}+\frac{1}{119}-\frac{1}{120}-\frac{1}{121}-\frac{1}{122}\ne0\)
Nên x + 116 = 0
<=> x = -116
Tìm x,biết:
a/ \(\frac{x}{3}-\frac{10}{21}=\frac{-1}{7}\)
b/x-25%=\(\frac{1}{2}\)
c/ \(\frac{-5}{6}+\frac{8}{3}+\frac{-29}{6}\le x\le\frac{-1}{2}+2+\frac{5}{2}\)
a) \(\frac{x}{3}-\frac{10}{21}=-\frac{1}{7}\)
\(\Rightarrow\frac{x}{3}=-\frac{1}{7}+\frac{10}{21}\)
\(\Rightarrow\frac{x}{3}=\frac{7}{21}\)
\(\Rightarrow\frac{x}{3}=\frac{1}{3}\)
\(\Rightarrow x=1\)
\(x-25\%=\frac{1}{2}\)
\(\Rightarrow x-\frac{1}{4}=\frac{1}{2}\)
\(\Rightarrow x=\frac{1}{2}+\frac{1}{4}\)
\(\Rightarrow x=\frac{3}{4}\)
c) \(-\frac{5}{6}+\frac{8}{3}+-\frac{29}{6}\le x\le-\frac{1}{2}+2+\frac{5}{2}\)
\(\Rightarrow-3\le x\le4\)
\(\Rightarrow x\in\left\{-3;-2;-1;0;1;2;3;4\right\}\)
a)x/3-10/21=-1/7
x/3=-1/7+10/21
x/3=1/3
=> x= 1
b/ x-25%=1/2
x-1/4=1/2
x=1/2+1/4
x=3/4
Tìm x :
a) \(\frac{x+1}{2000}+\frac{x+2}{1999}+\frac{x+ 3}{1998}+\frac{x+4}{1997}=-4\)
\(b.\frac{x+1}{1999}+\frac{x+2}{2000}+\frac{x+3}{2001}=\frac{x+4}{2002}+\frac{x+5}{2003}+\frac{x+6}{2004}\)
\(a.\left(\frac{x+1}{2000}+1\right)+\left(\frac{x+2}{1999}+1\right)+\left(\frac{x+3}{1998}+1\right)+\left(\frac{x+4}{1997}+1\right)=0\)
\(=\frac{x+2001}{2000}+\frac{x+2001}{1999}+\frac{x+2001}{1998}+\frac{x+2001}{1997}=0\)
\(=\left(x+2001\right).\left(\frac{1}{2000}+\frac{1}{1999}+\frac{1}{1998}+\frac{1}{1997}\right)=0\)
\(=>x+2001=0\)
\(x=-2001\)
\(b.\left(\frac{x+1}{1999}-1\right)+\left(\frac{x+2}{2000}-1\right)+\left(\frac{x+3}{2001}-1\right)=\left(\frac{x+4}{2002}-1\right)+\left(\frac{x+5}{2003}-1\right)\)\(+\left(\frac{x+6}{2004}-1\right)\)
\(\frac{x+1998}{1999}+\frac{x+1998}{2000}+\frac{x+1998}{2001}=\frac{x+1998}{2002}+\frac{x+1998}{2003}+\frac{x+1998}{2004}\)
\(\frac{x+1998}{1999}+\frac{x+1998}{2000}+\frac{x+1998}{2001}-\frac{x+1998}{2002}-\frac{x+1998}{2003}-\frac{x+1998}{2004}=0\)
\(\left(x+1998\right).\left(\frac{1}{1999}+\frac{1}{2000}+\frac{1}{2001}-\frac{1}{2002}-\frac{1}{2003}-\frac{1}{2004}\right)=0\)
\(=>x+1998=0\)
\(x=-1998\)
dễ quá!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
\(\frac{x+1}{2000}+\frac{x+2}{1999}+\frac{x+3}{1998}+\frac{x+4}{1997}=-4\)
\(\Leftrightarrow\left(\frac{x+1}{2000}+1\right)+\left(\frac{x+2}{1999}+1\right)+\left(\frac{x+3}{1998}+1\right)+\) \(\left(\frac{x+4}{1997}+1\right)=0\)
\(\Leftrightarrow\frac{x+2001}{2000}+\frac{x+2001}{1999}+\frac{x+2001}{1998}+\frac{x+2001}{1997}=0\)
\(\Leftrightarrow\left(x+2001\right)\left(\frac{1}{2000}+\frac{1}{1999}+\frac{1}{1998}+\frac{1}{1997}\right)=0\)
Mà : \(\frac{1}{2000}+\frac{1}{1999}+\frac{1}{1998}+\frac{1}{1997}\ne0\)
\(\Rightarrow x+2001=0\)
\(\Leftrightarrow x=-2001\)
1 Tìm x:
( \(3x-2\frac{1}{3}\)):( \(3\frac{1}{4}-5\frac{2}{3}+1\frac{4}{5}\)) = \(2-1\frac{1}{3}x\)
2. Tìm x:
\(\frac{x+\frac{2\left(3-x\right)}{5}}{14}-\frac{5x-4\left(x-1\right)}{24}=\frac{7x+2+\frac{9-3x}{5}}{12}+\frac{2}{3}\)
3. Tìm x:
\(\left(1+3x\right)^2-3x\left(2x+6\right)=\left(4-3x\right)\left(x+3\right)-\left(2x-1\right)^2\)
1) \(x=\frac{99}{196}\)
2) \(x=-2\)
3) \(x\approx-0,59\)
Bài 1: Tìm số nguyên n để phân số M=\(\frac{2n-7}{5n}\)có giá trị là số nguyên.
Bài 2: Tìm x biết :
a) / x - 3 /=2.(x + 2)
b) \(1\frac{1}{3}\div(24\frac{1}{6}-24\frac{1}{5})-\frac{1\frac{1}{2}-\frac{3}{4}}{4x-\frac{1}{2}}=-1\frac{1}{15}\div(8\frac{1}{5}-8\frac{1}{3})\)
Giúp mình với.
tìm x, biết : \(21+\frac{12}{2+\frac{1}{3+\frac{1}{4+\frac{1}{x}}}}=\frac{2011}{2+\frac{3}{4+\frac{5}{6+\frac{7}{8}}}}\) (máy tính casio)
\(4+\frac{1}{x}=\frac{4x+1}{x}\)
\(\frac{1}{4+\frac{1}{x}}=\frac{x}{4x+1}\)
\(3+\frac{1}{4+\frac{1}{x}}=3+\frac{x}{4x+1}=\frac{13x+3}{4x+1}\)
Tương tự Vế Trái sẽ tìm đc
\(21+\frac{12\left(13x+3\right)}{30x+7}\)
Vế phải bấm máy tính nhá casio mà
\(VP=\frac{104052}{137}=21+\frac{101175}{137}\)
Suy ra
\(\frac{156x+36}{30x+7}=\frac{101175}{137}\Leftrightarrow21375x+4932=3035250x+708225\)
\(\Leftrightarrow1004625x=-234431\Leftrightarrow x=-\frac{234431}{1004625}\)
tìm x biết
\(a,2\frac{1}{3}+\left(x-\frac{3}{2}\right)=\left(3-\frac{3}{2}\right).x\)
\(b,\frac{3}{2}:\left(x-1\frac{2}{3}\right)-5\frac{2}{3}=2\frac{5}{3}\)
\(c,\left(\frac{7}{2}-2x\right):3\frac{2}{5}+1\frac{4}{5}=7\frac{6}{5}\)
Cho x , y > 0 và \(\frac{4}{x^2}+\frac{5}{y^2}\ge9\) . Tìm min K = \(2x^2+\frac{6}{x^2}+3y^2+\frac{8}{y^2}\)
Tìm X
\(\frac{1}{4}\cdot\frac{2}{6}\cdot\frac{3}{8}\cdot\frac{4}{10}\cdot\frac{5}{12}\cdot.......\cdot\frac{30}{62}\cdot\frac{31}{64}=4^x\)
1/4.2/6.3/8.4/10.........30/62.31/64=4x
=1/2.1/2.1/2.1/2.............1/2.1/64=4^x
=1/2^30.1/2^6=4^x
=1/2^36=4^x
=1/4^18=4^x
=>x=-18