У=9х+8
у=2015
2015=9х+8
9х=2015-8
9х=2007
х=2007 : 9
х=223
<span>Ответ: 2)</span>
21x+4=15x+20
21x-15=20-4
6x=16
3x=8
×=2.6
<span>(6/13:1целая5/13+2/3)-0,375 = 0,625
6/13: 1 5/13=6/13:18/13=6/13*13/18=1/3
1/3+2/3=1
1-0,375=0,625
</span>
3 1/6 - 5/6= 3*6+1/6-5/6=19/6-5/6=14/6=2 2/6
2 1/4-3/4=9/4-3/4=6/4=1 2/4
4 3/8-5/8=35/8-5/8=30/8=3 6/8
5 5/12-11/12=65/12-11/12=54/12=48 6/12