1) (a+6) × (a+6) =a²+6a+6a+36 = a²+12a+36
2) 2a × (3-2a) =6a-4a²
3) a²+12a+36+6a-4a² = (4a²-a²)+18a+36
4(sinx-cosx)=(sinx-cosx)^2
sinx-cosx=0
tgx=1
x=pi/4+pik
sinx-cosx=1/4
sin(x-pi/4)=sqrt(2)/8
x=arcsin(sqrt(2)/8)+pi/4+2pik
x=П-arcsin(sqrt(2)/8)+pi/4+2pik