Tính
A = \(\frac{0,6-\frac{1}{3}+\frac{3}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}\)
Tìm x,y,z biết:
\(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}vàx-2y+3z=-10\)
\(\frac{x}{5}=\frac{y}{6}và2x^2-y^2=56\)