Упростите выражения: 1 3/4x - 3 7/11y + 21/4x - 5 4/11y 2 -1 5/12m - 5/7n - 7/12m - 2/7n ...

Решите задачу:

$1 \frac{3}{4} x-3 \frac{7}{11}y+2 \frac{1}{4}x-5 \frac{4}{11}y=$
$= \frac{7}{4}x- \frac{40}{11}y+ \frac{9}{4}x- \frac{59}{11}y=$
$=x( \frac{7}{4} + \frac{9}{4} ) -y( \frac{40}{11}+ \frac{59}{11} ) =$
$= \frac{16}{4}x- \frac{99}{11}y=4x-9y$

$-1 \frac{5}{12}m- \frac{5}{7}n- \frac{7}{12}m- \frac{2}{7}n=$
$=-m( \frac{17}{12}+\frac{7}{12} ) -n( \frac{5}{7}+ \frac{2}{7}) =$
$=- \frac{24}{12}m- \frac{7}{7}n=-2m-n$