А)(6a-3)(a+1)-3a(2a-3)
6a²+6a-3a-3-6a²+9a
12a-3
б)36x(x+2)-(6x+1)²
36x²+72x-36x²+12x+1
84x+1
в)4(c-3)²-(2c-7)(7+2c)
4(c-3)²-(2c-7)(2c+7)
4*c²-6c+9-4c²-49
4c²-6c+9-4c²-49
-6c-40
5*(sina - 4cosa) = 3*(3sina + 4cosa)
5sina - 20cosa = 9sina + 12cosa
-4sina = 32cosa
tga = -8
tg(2a) = 2tg(a)/(1 - tg^2(a)) = 2*(-8)/(1 - 64) = 16/63
0,15х-0,6=9,9-0,3х+0,3
0,15х+0,3х=10,2+0,6
0,45х=10,8
х=24
1. б) (3y-3)/(3y-2)+(6+2y)/(3y+2)=2
((3y-3)(3y+2)+(6+2y)(3y-2)-2(9y²-4))/(9y²-4)=0
(3y-3)(3y+2)+(6+2y)(3y-2)-2(9y²-4)=0 9y²-4≠0
3y²+6y-9y-6+12y+6y²-12-4y-18y²+8=0 9y²≠4
-9y²+5y-10=0 y²≠4/9
D=b²-4ac=25-360=-335 y≠2/3