а(1) = -10
d=0.5
a(n) = -10+0.5(n-1)
a(n) <2, n-?
-10+0.5(n-1)<2
-10+0.5n-0.5<2
0.5n < 2+10+0.5
0.5 n < 12.5
n< 25
n=24
a(24)<2
а(1) = -10
d=0.5
a(n) = -10+0.5(n-1)
a(n) <2, n-?
-10+0.5(n-1)<2
-10+0.5n-0.5<2
0.5n < 2+10+0.5
0.5 n < 12.5
n< 25
n=24
a(24)<2