A=\(-\dfrac{68}{123}\)x\(-\dfrac{23}{79}\)
B=\(-\dfrac{14}{79}\)x\(-\dfrac{68}{7}\)x\(-\dfrac{46}{123}\)
C=\(-\dfrac{4}{19}\)x\(-\dfrac{3}{19}\)x\(-\dfrac{2}{19}\) ... \(\dfrac{2}{19}\)x\(\dfrac{3}{19}\)x\(\dfrac{4}{19}\)
a)So sánh A,B,C
b)Tính B:A
\(\dfrac{19}{8}\)x\(\dfrac{16}{9}\)+\(\dfrac{19}{8}\)x\(\dfrac{2}{9}\)-\(\dfrac{19}{8}\)
Tính P = x+y+z biết:
\(\dfrac{19}{x+y}+\dfrac{19}{y+z}+\dfrac{19}{z+x}=\dfrac{5x}{y+z}+\dfrac{5y}{z+x}+\dfrac{5z}{x+y}=\dfrac{2015}{19}\)
Tính tổng \(x+y+z\) biết \(\dfrac{19}{x+y}+\dfrac{19}{y+z}+\dfrac{19}{z+x}=\dfrac{7z}{x+y}+\dfrac{7z}{z+x}=\dfrac{133}{10}\)
Đó mời giải
Tính tổng \(x+y+z\) biết \(\dfrac{19}{x+y}+\dfrac{19}{y+z}+\dfrac{19}{z+x}=\dfrac{7z}{x+y}+\dfrac{7z}{z+x}=\dfrac{133}{10}\)
Rồi bảo ai dốt
Tìm số nguyên x thỏa mãn điều kiện
\(\dfrac{-19}{23}\) < \(\dfrac{7}{x}\) < \(\dfrac{-19}{25}\)
Thực hiện phép tính ( tính nhanh nếu có thể ) :
a) \(\dfrac{3}{5}+\dfrac{1}{5}.\dfrac{-17}{9}\)
b) \(\left(-\dfrac{4}{15}-\dfrac{18}{19}\right)-\left(\dfrac{20}{19}+\dfrac{11}{15}\right)\)
Thực hiện phép tính (tính nhanh nếu có thể):
a/ \(\dfrac{3}{5}+\dfrac{1}{5}.\dfrac{-17}{9}\) b/ \(\left(-\dfrac{4}{15}-\dfrac{18}{19}\right)\)-\(\left(\dfrac{20}{19}+\dfrac{11}{15}\right)\)
bài 2: 1, \(\left(\dfrac{5}{6}\right)^{10}.\left(\dfrac{3}{10}\right)^{10}\)2,\(\left(\dfrac{4}{7}\right)^{19}:\left(\dfrac{-12}{35}\right)^{19}\) 3,\(\left(\dfrac{-3}{7}\right)^7:\left(\dfrac{-3}{5}\right)\)
Tìm x,y biết: \(\dfrac{x}{19}=\dfrac{y}{21}\)và 2x -y = 34.
A.x = 38; y = 42; B.x = -38; y = -42; C. x = 21; y = 19 D.x = -21; y = -1