\(\frac{-5}{x}\)=\(\frac{y}{16}\)=\(\frac{-18}{72}\)
y.72 = 16.(-18)
y = -288:72
y = -4.
x.(-4) = -5.16
x = -80:(-4)
x = 20.
Vậy x =20 ; y = -4
Tìm x,y thuộc Z
a) \(\frac{-5}{x}\) = \(\frac{y}{16}\) =\(\frac{-18}{72}\)
b) \(\frac{x}{3}\) =\(\frac{5}{y}\)
c)\(\frac{x}{y}\) =\(\frac{28}{35}\)
bài 1 : tính
a)\(\frac{-5}{13}-\left(\frac{3}{5}+\frac{3}{13}-\frac{4}{10}\right)\) b) \(\left(\frac{3}{9}-\frac{9}{18}\right)+\frac{3}{6}-\left(\frac{1}{3}-\frac{1}{2}\right)-\frac{5}{15}\) c) \(\frac{9}{18}+\frac{16}{32}-\frac{12}{46}-\frac{9}{17}\) d) \(\left(\frac{14}{18}+\frac{-16}{27}\right)-\left(\frac{2}{3}-\frac{5}{15}\right)\)
tìm các số nguyên x,y,z,t biết \(\frac{-6}{12}\) = \(\frac{x}{8}\) = \(\frac{-7}{y}\) =\(\frac{z}{-18}\)=\(\frac{16}{t}\)
Tìm x, y thuộc Z
a) \(\frac{-2x}{5}\)= \(\frac{-6}{3}\)
b) \(\frac{x-2}{18}\) = \(\frac{-1}{6}\)
c) \(\frac{x}{14}\)= \(\frac{6}{y}\)=\(\frac{-15}{35}\)
Cho S= \(\frac{1}{11}+\frac{1}{12}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{16}+\frac{1}{17}+\frac{1}{18}+\frac{1}{19}+\frac{1}{20}\)
So sánh S với \(\frac{1}{2}\)
Tìm x,y biết :
a) \(\frac{3}{4}x+\frac{1}{5}=-\frac{1}{2}\)
b)\(-\frac{4}{5}+\left(\frac{1}{3}:y\right)=-\frac{5}{6}\)
Tìm số tự nhiên x, y sao cho : \(\frac{x}{9}\) - \(\frac{3}{y}\) = \(\frac{1}{18}\)
Tìm x thuộc Z biết
\(\frac{5}{3}\)+\(\frac{-14}{3}\) < x <\(\frac{8}{5}\)+\(\frac{18}{10}\)
Tìm x , y :
\(\frac{x+3}{y+5}=\frac{3}{5}\) va x + y = 6
\(\frac{x-7}{y-6}=\frac{7}{6}va\) x - y = -4
