3m-6n=3(m-2n)
2n-4q=2(n-2q)
x^2-3xy=x(x-3y)
-mc-c=c(-m-1)
5^2+5^2=5(5+5)
4q^2-9b^2=(4q-9b)(4q+9b)
3c^3=3cd^2; 3c^3-3cd^2=3c*c^2-2cd+d^2
√5(√3+√7)=√15+√35<span>
(√10 -√3)(√10 + √3)= </span>√10² -√3²= 10-3=7
Sin3x=-1/2
sin 7π/6=-1/2,sin 11π/6=-1/2
a)3x=7π/6+2k.π, x=7π/18+2k.π/3
b)3x=11π/6+2k.π, x=11π/18+2k.π/3
k=0,1,-1,2,-2,..... k∈Z