Y`=(3sin6x)`*(6x)`-(sin18x)`*(18x)`=3cos6x*6 -cos18x*18=
=18cos6x-18cos18x=18(cos6x-cos18x)
или
18*(-2sin(-6x)sin12x)=36sin6x*sin12x
X^2+x-6=0; D=1^2-4*1*(-6)=1+24=25;x1=(-1-5)/2, x2=(-1+5)/2. x1= -3, x2=2. x^2+x-6=(x+3)*(x-2). Ответ: x1= -3, x2=2.
A) 5(х-1)+7 ≤ 1-3(х+2)
5х-5+7 ≤ 1-3х-6
5х+2 ≤ -3х-5
5х+3x ≤ -2-5
8x ≤-7
x≤-7/8
б) 6х-(х+8)-3(2-х) ≤ 2
6x-x-8-6+3x≤ 2
8x-14≤ 2
8x≤ 16
x≤ 2