A8=a1+7d
a23=a1+22d
a1+7d=0.6
a1+22d=2.1
a1=0.6-7d
a1=2.1-22d
0.6-7d=2.1-22d
15d=1.5
d=0.1
5,6/¥+0.6=0.3
5,6/¥=0.3-1.6
5.6/¥=0.14
5.6=0.14¥
¥=5.6/0.14=4
(8/15 + 2/9х)/ 3/5 = 2
8/15 + 2/9х = 2 × 3/5
8/15 + 2/9х = 1,2
8/15 + 2/9х - 1,2 = 0
8/15 - 1 2/10 + 2/9х = 0
16/30 - 1 6/30 + 2/9х = 0
16/30 - 36/30 + 2/9х = 0
-20/30 + 2/9х = 0
2/9х = 20/30
х = 20/30 : 2/9
х = 20/30 × 9/2
х = 180/60
х = 3