4 1\5*3\2=21\5*3\2=63\10=6 3\10дм-длина
2(4 1\5+6 3\10)=2(4 2\10+6 3\10)=2*10 5\10=2*10 1\2=2*21\2=21дм
4 1\5*6 3\10=21\5*63\10=1323\50=26 23\50 дм2-площадь
(37/4-26/3)×12/7+(38/9-17/6):4/3=((111-104)/12)×12/7+((76-51)/18)×3/4=7/12 × 12/7 + 25/18 × 3/4=1+ 25/24=2_1/24
6440 /7
-63 /920
-------------
14
- 14
-------
0
4680/8
-40 /585
-------------
68
-64
----------------
40
-40
------------------
0
22680/9
-18 /2520
--------------
46
-45
-----------
18
-18
--------------------
0
14090/5
-10 /2818
--------------
40
-40
------------
9
-5
---------------
40
-40
-------------------
0
17490/5
-15 / 3498
----------------
24
-20
----------------
49
-45
-------------
40
-40
---------------
0
<span>1,5(-2,4a+3,8b)-1,6(2,5a-b) =
</span>(-2,4a×1,5+3,8b×1,5)-(2,5a×1,6-1,6b) =
-2,4a×1,5+3,8b×1,5-2,5a×1,6+1,6b =
-3,6a + 5,7b - 4a +1,6b = 7,3b - 7,6a