1) 1 17/18 * 1 13/14 = 35/18 * 27/14 = 45/12
2) 2 5/8 : 1 19/20 = 21/8 : 39/20 = 21/8 * 20/39 = 35/26
3) 45/12 - 35/26 = 585/156 - 210/156 = 375/156
4) 2 25/78 - 1 1/26 = 181/78 - 27/26 = 181/78 - 81/78 = 100/78
5) 375/156 : 100/78 = 375/156 * 78/100 = 15/8 =1 7/8
14x + 27x =646 81y-38y=645
(z-1,2)/0,6=21,1
z-1,2=21.1*0,6
z-1,2=12,66
z=12,66+1,2
z=13.86
3,5m+m=9,9
4,5m=9,9
m=9,9/4,5
m=2,2
4х+3у= -4 ( *-3)
6х+5у= -7 ( *2)
-12х-9у=12
12х+10у=-14
у=26
4х+3у= -4
у=26
4х+3*26= -4
у=26
4х= -82
у=26
х= - 20,5
(-20,5; 26)
х+5у=7
3х-2у=4
х=7-5у
3(7-5у)-2у=4
х=7-5у
21-15у-2у=4
х=7-5у
-17у= - 17
х=7-5у
у=1
х=2
у=1
(2; 1)