2) 21/12 и 41/12 (1 целая 9/12; 3 целых 5/12)
4)135/100 и 206/100 (1 целая 35/100; 2 ц. 6/100)
6)7/100 и 490/100 (7\100; 4 целых 9/10)
8)275/90 и 24/90 (3 целых 5/90; 24/90)
123000мм=12300см
12300:30=410см=41дцм
410см=4м10см
<span>(5/18+7/12)*2 10/31+1 13/51:(4/17-20\51)=
5/18+7/12=10/36+21/36=31/36
2 10/31=72/31
31/36* 72/31=72/36=2
4/17-20/51=12/51-20/51=-8/51
1 13/51=64/51
64/51:(-8/51)=-64/51*51/8=-64/8=-8
2+(-8)=2-8=-6
</span>
Х = 259/37
х = 7
Проверка - 7*37 = 259