Sqrt(2)=1,42
sqrt(3)=1,73
sqrt(5)=2,23
sqrt(7)=2,64
<span>а20=а1+19d=40-7,6=32,4</span><span>
S20(сумма 20 членов)=((а1+а20)/2)*20=((40+32,4)/2)*20=724
Ответ: 724</span>
1)х-3≤3х-1, х+1≤4
-2≤2х, х≤3
-1≤х, х≤3
-1≤х≤3
<span>2) 3х+1> x+5? 5x-4>6
</span><span>2х> 4, 5x>10
</span><span>х> 2, x>2
</span><span><span>x>2
</span>3) x+1≤ 7, 4x>3x-2</span>
x≤ 6, x>-2
-2<x≤ 6