5,4(3y-2)-7,2(2y-3)=1,2;
16,2y-10,8-14,4y+21,6=1,2;
1,8y+10,8=1,2;
1,8y=-9,6;
y=-16/3;
y=-5⅓
1) находим 1%
48:8=6
2) находим 100%, то есть число
6*100=600
28cos x -3sin x-8=0
sin x=2tg (x/2) /(1+tg^2 (x/2));
cosx=(1-tg^2 (x/2)) /(1+tg^2 (x/2))
28*(1-tg^2 (x/2)) /(1+tg^2 (x/2)) - 3*2tg(x/2) /(1+tg^2 (x/2) -8=0
1+tg^2 (x/2)≠0; 28*(1-tg^2 (x/2)) -6tg(x/2)-8*(1+tg^2 (x/2))=0
28 - 28tg^2 (x/2) - 6tg(x/2)-8 - 8tg^2 (x/2)=0
-36tg^2 (x/2)-6tg (x/2)+20=0
18tg^2 (x/2)+3tg(x/2)-10=0
tg(x/2)=t; 18t^2 +3t-10=0; D=9-4*18*(-10)=9+720=729=27^2;
t1=(-3-27)/36=-30/36=-5/6; t2=24/36=4/6=2/3
tg(x/2)=-5/6 ili tg(x/2)=2/3
x/2=-arctg(5/6)+πn x=2*arctg(2/3)+2*πn; n-celoe
x=-2arctg(5/6)+2πn ------------------------------------
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6+2*1.5 х - 2*3 = 6 + 3 х - 6 = 3 х