Пошаговое объяснение:

9/16-1(16x/3-1*2/3-y)-1*7/20-1(20/7-x-1*40/7-y)

9/16-1*16x/3+2/3+y-1*7/20-1(20/7-x-1*40/7-y)

9/16+-16x/3+2/3+y-7/20-1(20/7-x-40/7-y)

9/16+-16x/3+2/3+y-7/20+x+y+20/7

6277/1680+-16x/3+2y+x