Cos(3x - π/2) = 1/2
sin3x = 1/2
3x = (-1)^n*arcsin(1/2) + πk,k∈Z
3x = (-1)^(n)(π/6) + πk, k∈z
x = (-1)^(n)(π/18) +πk/3, n∈Z
1)x²+7x+12=0
x1+x2=-7 U x1*x2=12⇒x1=-4 U x2=-3 Б
2)2x²-x-1=0
D=1+8=9
x1=(1-3)/4=-1/2
x2=(1+3)/4=1 A
3)4x²-12x+9=0
(2x-3)²=0
2x-3=0
2x=3
x=1,5
Log0,6(2x-2)=0
log0,6(2x-2)=log0,6(1)
2x-2=1
2x=3
x=3/2