270-a=170+30
270-a=200
a=270-200
a=70
---------------------
270-70=170+30
200=200
-9(8-9х)=4х+5
-72+81х=4х+5
81х-4х=5+72
77х=77
х=77:77
х=1
Проверка
-9(8-9*1)=4*1+5
-9*(-1)=4+5
9=9
3х.кв- 241=0 3х.кв=241 (3×3)=9
9х =241 х=241:9 х=26,8
1.792:(-11)=-72
2.226:(-2)=-113
3.432-(-72)=504
4.504+(-113)=391
Со знаменателем 9: 7/9; 45/9; 6/9; 3/9; 4/9; 3/9; 6/9; 21/9; 8/9; 3/9; 5/9; 5/9; 6/9; 3/9; 12/9.
Со знаменателем 24: 18/24; 24/24; 23/24; 3/24; 8/24; 5/24; 4/24; 16/24; 15/24; 6/24; 9/24; 20/24; 12/24; 21/24; 7/24.
Со знаменателем 28:
3/28; 26/28; 16/28; 14/24; 18/28; 280/28; 21/28; 22/28; 23/28; 12/28; 8/28; 7/28; 10/28; 17/28; 24/28.
Со знаменателем 48:
16/48; 9/48; 28/48; 12/48; 24/48; 36/48; 40/48; 8/48; 1/48; 240/48; 11/48; 32/48; 20/48; 10/48; 48/48.