1) 6/3 =6*1/3 = 2
2) 63/(-3) = 63* (-1/3) = -21
3) -23/ (- 1/2) = -23 *(-2) = 46
4) -5 /25 = -5 * 1/25 = -0,2
5) -2/3 ÷4/9 = -2/3 *9/4 = -1,5
6) 7÷ (-7/8) = -8
28-20х-12+20х=28-12=61
6х-2y-5x+2y=x
6x+12y-6x-3y=9y
20x+5y-2x+2y=18х+7y
11/6, 31/32, 5/8
11/20, 7/12, 5/8