3х - 3у+5х=6х-4
3х+5х+6х-3у=-4
14х=-4
х=-4:14
х=0,
При а = 5.3
3*5.3+5*5.3-4*5.3-2=15.9+26.5-21.2-2=19.2
при а 1/3
3*1/3+5*1/3-4*1/3-2=1+1.6-1.3-2=-0.7
3sin13/12П * cos 13/12П= 3*2/2<span>sin13/12П * cos 13/12П=
=3/2*2</span><span>sin13/12П * cos 13/12П = 3/2*Sin26/12</span>π = 1,5Sin(2π + π/6) =
= 1,5Sinπ/6 = 1,5 *1/2 = 0,75
При равняем к нулю:
(x-5)=0; x=5;
(2x+7)=0; 2x=-7; x=-7/2;
X=5
X=-3,5
Ответ: -3,5; 5;