а2•а5=а10
(¬_¬)(¬_¬)(¬_¬)(¬_¬)-_-||
18-d+4d= -9
18+3d= -9
3d= -9-18
3d= -27
d= -9
a1=18- (-9)=18+9=27
a10=a1+9d=27+9×(-9)=27-81= -54
а2•а5=а10
(¬_¬)(¬_¬)(¬_¬)(¬_¬)-_-||
18-d+4d= -9
18+3d= -9
3d= -9-18
3d= -27
d= -9
a1=18- (-9)=18+9=27
a10=a1+9d=27+9×(-9)=27-81= -54