2 1/10 : 1 2/5 = 21/10 : 7/5 = 21/10 * 5/7 = 3/2 * 1/1 = 3/2 = 1 1/2 = 1,5
МК=ME-KE
EF=MF-ME
26-18=8 см- МК
<span>43-26=17см- ЕF</span>
166842|____207
-1656 86
____
1242
-1242
_____
0
207
* 86
_____
17802
7,5(а+а²)-2,5(а+3а²)=7,5а+7,5а²-2,5-7,5а²=7,5а-2,5а=5а=5×0,12=,06