\(\dfrac{-7}{8}=\dfrac{14}{x}\)
\(x=-\dfrac{14\times8}{7}\)
\(x=-16\)
\(\dfrac{-7}{8}=\dfrac{14}{x}\)
\(x=-\dfrac{14\times8}{7}\)
\(x=-16\)
a)\(\dfrac{2}{3}\)x-1=\(\dfrac{3}{2}\)
b)| 5x - \(\dfrac{1}{2}\)| - \(\dfrac{2}{7}\)= 25%
c)\(\dfrac{x-3}{4}\)=\(\dfrac{16}{x-3}\)
d)\(\dfrac{-8}{13}\)+\(\dfrac{7}{17}+\dfrac{21}{31}\)<x≤\(\dfrac{-9}{14}\)+4+\(\dfrac{5}{-14}\)(xϵZ)
Tìm x:
\(a,\dfrac{8}{14}=\dfrac{x+1}{7}\) \(b,\dfrac{-4}{3}=\dfrac{5x+1}{-27}\)
1. tìm các số chưa biết :
a) \(\dfrac{4}{3}\)= \(\dfrac{8}{x}\)=\(\dfrac{-y}{21}\)=\(\dfrac{-40}{z}\)=\(\dfrac{16}{t}\)=\(\dfrac{y}{111}\)
b) \(\dfrac{-7}{6}=\dfrac{x}{18}=\dfrac{-98}{y}=\dfrac{14}{y}=\dfrac{-14}{z}=\dfrac{t}{102}=\dfrac{4}{-78}\)
2. tìm x biết :
a) \(\dfrac{2}{x}=\dfrac{x}{8}\)
b) \(\dfrac{2x-9}{240}=\dfrac{39}{80}\)
c) \(\dfrac{x-1}{9}=\dfrac{8}{3}\)
mn giúp mk nha :>
bài 14: tính
a,\(\dfrac{4}{5}\) + \(\dfrac{1}{4}\) x \(\dfrac{2}{3}\)
b,\(\dfrac{7}{12}\) + \(\dfrac{3}{4}\) : \(\dfrac{3}{8}\) - \(\dfrac{1}{4}\)
\(\dfrac{1}{5}+\dfrac{2}{11}< \dfrac{x}{55}< \dfrac{2}{5}+\dfrac{1}{5}\) \(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6}< x\le\dfrac{13}{4}+\dfrac{14}{8}\)
\(\dfrac{1}{4}+\dfrac{5}{12}+\dfrac{-1}{13}< x< \dfrac{7}{5}+\dfrac{2}{10}+\dfrac{1}{2}\) \(\dfrac{79}{15}+\dfrac{7}{5}+\dfrac{-8}{3}\le x\le\dfrac{10}{3}+\dfrac{15}{4}+\dfrac{23}{12}\)
Thực hiện phép tính (tính hợp lý nếu có thể):
a) \(\dfrac{5}{9}.\dfrac{7}{13}+\dfrac{5}{9}.\dfrac{8}{13}-\dfrac{5}{13}.\dfrac{2}{9}\) b) \(12\dfrac{5}{14}-\left(3\dfrac{5}{7}+5\dfrac{5}{14}\right)\)
c)\(\dfrac{-2}{5}+\dfrac{7}{11}+\dfrac{-11}{10}+\dfrac{7}{-11}\) d) \(\dfrac{1}{2}+\dfrac{-2}{3}+\dfrac{1}{6}+\dfrac{-2}{5}\)
tính
a)\(\dfrac{-10}{11}.\dfrac{8}{9}+\dfrac{7}{18}.\dfrac{10}{11}\)
b)\(\dfrac{3}{14}:\dfrac{1}{28}-\dfrac{13}{21}:\dfrac{1}{28}+\dfrac{29}{42}:\dfrac{1}{28}-8\)
c)\(-1\dfrac{5}{7}.15+\dfrac{2}{7}\left(-15\right)+\left(-105\right).\left(\dfrac{2}{3}-\dfrac{4}{5}+\dfrac{1}{7}\right)\)
Bài 4: So sánh:
a. \(\dfrac{2}{3}\)và\(\dfrac{1}{4}\)
b. \(\dfrac{7}{10}\)và\(\dfrac{7}{8}\)
c. \(\dfrac{6}{7}\)và\(\dfrac{3}{5}\)
d. \(\dfrac{14}{21}\)và\(\dfrac{60}{72}\)
Tìm x
b)\(\left(x-\dfrac{1}{2}\right):\dfrac{1}{3}+\dfrac{5}{7}=9\dfrac{5}{7}\)
c) \(\dfrac{1}{2}x-\dfrac{3}{4}=\dfrac{14}{9}.\dfrac{3}{7}\)