7/9t +11/12 = 13/18
7/9t = 13/18 -11/12 = 26/36 - 33/36
7/9t= - 7/36
t = - 7/36 :7/9 ( -7/9 x 9/7)
t = -1/4
7/9 x (-1/4) +11/12 =13/18
11/13 -7/36 =13/18
33/36 - 7/36 =13/18
26/36=13/18
13/18=13/18
5/21y -2 = 3 1/14
5/21y = 3 1/14 +2 =5 1/14
y= 5 1/14 : 5/21
y= 71/14 x 21/5 = 1491/70 = 21 21/70
5/21x 21 21/70-2 =3 1/14
5/21 x 1491/70 - 2 =3 1/14
7455/1470 -2 =3 1/14
5 1/14 -2 =3 1/14
3 1/14 = 3 1/14
1.
5348+726+17629=23703
1) 5348+726=6074
2) 6074+17629=23703
2.
138548+629+15238=154 415
1) 138 548 + 628=139 177
2) 139 177 + 15 238 = 154 415
3.
82363+2747+684=85 804
1) 82 363+2747= 85 110
2) 85 110 + 694 = 85 804
Половина часа- 30 минут
Треть- 20 минут
Четверть- 15 минут
-1/2 а=(-4;2;1), отсюда с=в-1/2 а=(2-4;-2+2;-1+1)=(-2;0;0).