4х+3-10Х-11=7+13-4Х
-6Х-8=20-4Х
-2х=28
Х=-14
a9 = a10 - d, а так как a10 = d, то a9 = d - d = 0
Logx=t
1/5-t+2/1+t
1+t+10-2t=(5-t)(1+t)
11-t=5+4t-t^2
t^2-5t+6=0
D=5^2-4*1*6=1^2
t=3
t=2
Lgx=3
X=1000
Lgx=2
X=100
a)x-2>=0
x>=2
[2;+beskonechnost)
b) (-beskonechnost;-3) dalshe leqko