(2,5-3x):1\(\dfrac{2}{3}\)=(\(\dfrac{5}{8}\)+2x):(\(\dfrac{-8}{17}\))
=>(2,5-3x).\(\dfrac{3}{5}\)=(\(\dfrac{5}{8}\)+2x).\(\dfrac{-17}{8}\)
=>\(\dfrac{7,5-9x}{5}\)=\(\dfrac{-10,625+\left(-34\right)x}{8}\)
=>60-72x=-53,125-170x
=>60+53,125=72x-170x
=>113,125=-98x
=>x=\(\dfrac{-905}{784}\)
Vậy x=\(\dfrac{-905}{784}\)
(2,5 - 3x) : \(1\dfrac{2}{3}=\left(\dfrac{8}{5}+2x\right):\left(-\dfrac{8}{17}\right)\)
Tìm hai số x,y biết
a/\(\dfrac{x^3}{8}=\dfrac{y^3}{27}=\dfrac{z^3}{64};x^2+2y^2-3z^2=-650\)
b/\(\dfrac{x-1}{2}=\dfrac{y+3}{4}=\dfrac{z-5}{6};5z-3x-4y=50\)
1,2x :\(\dfrac{5}{7}\)=\(\dfrac{14}{15}\) : \(\dfrac{3}{2}\)
2,\(\dfrac{9}{10}\) :(3x) = \(\dfrac{5}{3}:\dfrac{20}{27}\)
3,\(\dfrac{x-2}{27}=\dfrac{3}{x-2}\)
4,\(\dfrac{2x+5}{9-2x}=\dfrac{2}{5}\)
5,\(\dfrac{x-7}{x+8}=\dfrac{x-8}{x+9}\)
Tìm x:
1) \(\dfrac{1,2}{30}\)\(=\dfrac{3x+4}{50}\)
2) \(\dfrac{x-1}{x-5}\)\(=\dfrac{6}{7}\)
3) \(\dfrac{x-1}{3}\)\(=\dfrac{x+3}{5}\)
4) \(\dfrac{3}{7}\)\(=\dfrac{2x+1}{3x+5}\)
5) \(\dfrac{2x+3}{3x+1}\)\(=\dfrac{3}{4}\)
6) \(\dfrac{2x+3}{6}\)\(=\dfrac{7x-3}{15}\)
7) \(\dfrac{6x-5}{-7}\)\(=\dfrac{5x-3}{-5}\)
8) \(\dfrac{x+1}{x-2}\)\(=\dfrac{3}{4}\)
9) \(\dfrac{2x-3}{x+1}\)\(=\dfrac{4}{7}\)
10) \(\dfrac{2x+3}{7}\)\(=\dfrac{4x-1}{15}\)
11) \(\dfrac{2x+3}{24}\)\(=\dfrac{3x-1}{32}\)
12) \(\dfrac{2x+4}{7}\)\(=\dfrac{4x-2}{15}\)
13) \(\dfrac{11x-2}{7x+5}\)\(=\dfrac{11}{8}\)
14) \(\dfrac{12-7x}{-13}\)\(=\dfrac{4-3x}{-5}\)
15) \(\dfrac{52}{2x-1}\)\(=\dfrac{13}{30}\)
bài tìm x,y,z biết :a)\(\dfrac{x}{5}=\dfrac{y}{6};\dfrac{y}{8}=\dfrac{z}{7}\)và x+y-z=69
b)\(\dfrac{x}{3}=\dfrac{y}{4};\dfrac{y}{3}=\dfrac{z}{5}\)và 2x-3y+z=6
c)\(\dfrac{x}{2}=\dfrac{y}{5}=\dfrac{z}{6}\)và x+y=14
d)\(\dfrac{2}{3x}=\dfrac{1}{2y}=\dfrac{2}{z}\)và 3x+2y+z=1
Bài 1: Tìm x biết
a) \(\dfrac{5}{6}\) : x = 30:3
b) x : 2,5 = 0,003:0,75
c) 3,8 : (2x) = \(\dfrac{1}{4}\) : 2\(\dfrac{2}{3}\)
d) \(\dfrac{2}{3}\) : 0,4 = x : \(\dfrac{4}{5}\)
f) 3\(\dfrac{4}{5}\) : 40\(\dfrac{8}{15}\) = 0,25 : x
e) \(\dfrac{x}{-15}\) = \(\dfrac{-60}{x}\)
bài 1 : tì tỉ lệ thức \(\dfrac{a}{b} = \dfrac{c}{d}\) hãy suy ra
a, \(\dfrac{a}{a+b}\) = \(\dfrac{c}{c+d}\)
b, \(\dfrac{a}{a-b}=\dfrac{c}{c-d}\)
bài 2 : lập tỉ lệ thức có được từ các số sau
a, 3;4; 4 và 1 phần 2 ;5;6
b, 3;4;15;20
bài 3 : tìm x biết
a, \(\dfrac{x}{0,9}=\dfrac{5}{6}\)
b, \(\dfrac{14}{15}: \dfrac{9}{10}= x:\dfrac{3}{7}\)
c, \(\dfrac{-6}{x} = \dfrac{9}{-15}\)
d, 1 và 3 phần 5 chia 8 = 2,5 : x
e, \(\dfrac{x}{2}=\dfrac{8}{x}\)
g, \(\dfrac{3x-7}{8}=\dfrac{5}{2}\)
a) \(\dfrac{1,2}{x+3}=\dfrac{5}{4}\)
b) \(\dfrac{3}{5}:\dfrac{2x}{15}=\dfrac{1}{2}:\dfrac{4}{5}\)
c) \(\dfrac{-4}{2,5}:3,5=1,5:x\)
d)\(0,12:3=2x:\dfrac{3}{5}\)
1) \(\dfrac{-5}{\dfrac{12}{\left|\dfrac{2}{3}x+\dfrac{1}{2}\right|}}\)= \(\dfrac{\dfrac{-4}{9}}{\dfrac{8}{15}}\)
2) \(\dfrac{\left|3x-5\right|}{-3}\)= \(\dfrac{\dfrac{-5}{6}}{\dfrac{4}{9}}\)
