An=a1+d(n-1) a1+5d=3 a1+8d=18 a1=3-5d 3-5d+8d=18 3d=15 d=5 <span>a1=3-5*5=-22</span>
S = 560м; g = 10м/с^2
S = gt^2/ 2
560 * 2 = gt^2
gt^2 = 1120
10 t^2 = 1120
t^2 = 1120 : 10
t = Y112
t = 10,58
Ответ: за 10,58с тело пролетит 560м, т.е. достигнет земли.
-5х+9(-1+2х)=9х-1
-5х-9+18х-9х=-1
4х=-1+9
4х=8
х=2
<em><u>Ответ: 2.</u></em>
ОДЗ x^2-3<span>≠0</span>
x^2<span>≠3</span>
<span>x<span>≠корень 3</span></span>
<span><span>
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<span><span>ОДЗ</span></span>
x^2+6x-7<span>≠0</span>
<span>x1<span>≠1; x2<span>≠-7</span></span></span>