Упростить выражения 4/21*7/15*15/16n и 1 4/9*1 9/13x*1 7/11

$\frac{4}{21}\cdot\frac{7}{15}\cdot\frac{15}{16}n=\frac{4\cdot7\cdot15}{21\cdot15\cdot16}n=\frac{1\cdot1\cdot1}{3\cdot1\cdot4}n=\frac{1}{12}n$

$1\frac{4}{9}\cdot1\frac{9}{13}x\cdot1\frac{7}{11}=\frac{13}{9}\cdot\frac{22}{13}x\cdot\frac{18}{11}=\frac{13\cdot22\cdot18}{9\cdot13\cdot11}x=\frac{1\cdot2\cdot2}{1\cdot1\cdot1}x=4x$