Tìm x , y , z biết :
\(\begin{cases} \dfrac{2x}{5}=\dfrac{3y}{4}=\dfrac{4z}{5}\\ x+y+z=49 \end{cases}\)
Bài 2:Tìm x biết:
a)\(\dfrac{1}{7}+x=\dfrac{-2}{3}\)
b)\(\dfrac{-2}{3}:x=\dfrac{-5}{6}\)
c)\(\left\{\dfrac{3}{5}-2x\right\}.\dfrac{5}{8}=1\)
d)\(\dfrac{3}{4}+\dfrac{2}{5}x=\dfrac{29}{60}\)
e)\(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)
f)\(\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}\)
g)\(\left|X+\dfrac{1}{3}\right|-4=\dfrac{-1}{2}\)
h)\(\left(\dfrac{1}{32}\right)^x.8^{2x}=512\)
i)\(5,3x+\left(-3,3\right)x+1,7=-4,9\)
Tìm x , y và z biết :
\(\begin{cases} \dfrac{2x}{5}=\dfrac{3y}{2}=\dfrac{5z}{7}\\ xyz=504000 \end{cases}\)
Tìm x :
\(\dfrac{2}{5}.\left(1-\dfrac{1}{2}x\right)-2x=\dfrac{1}{5}\)
Tìm x , y và z biết :
\(\begin{cases} \dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}\\ 2x^2+y^2-z^2=9 \end{cases}\)
Tìm x , y và z biết :
\(\begin{cases} \dfrac{x}{3}=\dfrac{y}{4}=\dfrac{z}{5}\\ 2x^2+y^2-z^2=9 \end{cases}\)
\(\dfrac{1}{2.4}\)+\(\dfrac{1}{4.6}\)+ ..........+ \(\dfrac{1}{\left(2x-2\right).2x}\)= \(\dfrac{1}{8}\)( x thuộc N ; x lớn hơn hoặc bằng 2)
Tìm x biết
a, 7 . ( x - 3 ) - 2 . ( 2x - 1 ) = 1
b, ( 1 - 2x ) 2 = 4
c, \(\left|x-\dfrac{1}{2}\right|\) = \(\dfrac{1}{3}\)
d, ( 1 - x )3 = \(\dfrac{1}{8}\)
Tìm \(x,y\in Z\) biết
a) \(\dfrac{3}{x}+\dfrac{y}{3}=\dfrac{5}{6}\)
b)\(\dfrac{5}{x}-\dfrac{y}{3}=\dfrac{1}{6}\)
c)\(\dfrac{x}{6}-\dfrac{2}{y}=\dfrac{1}{30}\)
d)\(xy+2x-y=15\)