Bai 1:a)Tim x biet\(\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{2}{x\times\left(x+1\right)}=\frac{2009}{2011}\)
b)\(\left(x-1\right)\times f\left(x\right)=\left(x+4\right)\times f\left(x\right)\)voi moi x
Bai 2;Tim x;y;z biet a)\(\frac{y+z+1}{x}=\frac{x+z+2}{y}=\frac{x+y-3}{z}\) b)\(\frac{2x+1}{5}=\frac{3y-z}{7}=\frac{2x+3y-1}{6x}\)
3.Tim x,y,z biet
a,\(\frac{x}{5}=\frac{y}{7};x.y=315\)
b,\(5x=9y;2x+3y=-33\)
c,\(\frac{x}{5}=\frac{y}{7}=\frac{z}{9};2x+y-3z=20\)
d,\(\frac{x}{4}=\frac{5}{y}=\frac{z}{6};2x^2-y^2+\frac{1}{2}z^2=100\)
e,\(\frac{x}{5}=\frac{y}{4}=\frac{7}{7};x+y-z=-10\)
g, 2x=5y=3z;x-y+z=38
1) Tim x biet :
a) \(\frac{2}{3}x-70\frac{10}{11}:\left(\frac{131313}{151515}+\frac{131313}{353535}+\frac{131313}{636363}+\frac{131313}{999999}\right)=-5\)
2) a) Tim cac cap so thuc (x,y) sao cho x,y thoa man dong thoi 2 dieu kien sau:
x=\(x^2+y^2\)va \(y=2xy\)
tim x,y,z biet \(\frac{3.X-5.Y}{2}=\frac{5.Y-3.Z}{3}=\frac{3.B}{4};X+Y+Z+17\)=17
Tim cac so Nguyên x va y biet :
a) \(\frac{1}{y}+\frac{x}{4}=\frac{1}{2}\) b)\(\frac{5}{x}+\frac{y}{4}=\frac{1}{8}\)
tim cac cap so x,y biet:
\(\frac{x}{2}=\frac{y}{5}\)va x.y =90
\(\frac{3x-y}{x+y}=\frac{3}{4}\)tim\(\frac{x}{y}\)
Tim x, y biet
\(x-\frac{3}{5}=\frac{3}{5}\)
\(|x|-\frac{4}{5}=\frac{2}{5}\)
\(\frac{x}{-5}=\frac{24}{15}\)
\(\frac{x}{4}=\frac{y}{5}vax-y=21\)
Tim x,y,z biet
\(\frac{x}{10}=\frac{y}{5}:\frac{y}{2}=\frac{z}{3}và2x-3y+4z=330\)
tim x, y, z biet
1. \(\frac{x+y}{2015}=\frac{xy}{2016}=\frac{x-y}{2017}\)
2.\(\frac{2x+2}{3}=\frac{3y-1}{4}=\frac{4x+2}{5}\)va x+y+z=7