D = b²-4ac = 23²-4•120 = 529-480 = 49
x = 23±7/2
x1 = 30/2 = 15
x2 = 8
-2sin2xcos3x/(-2sin2xsin3x)*(1-cos6x)=cos3x/sin3x *2sin²3x=
=2cos3xsin3x=sin6x
<span>2|х| = 8
</span><span>|х| = 4
х₁=4 х₂=-4
х₁*х₂=-4*4=-16
</span><span> (х+6)*(х-2)=0
х₁+6=0 х₁=-6
х₂-2=0 х₂=2
х₁+х₂=-6+2=-4</span>
D = 49-40=9; Корень D = 3
x1 = 7+3/10 = 1
х2 = 7-3/10 = 4/10 = 0,4
ответ: 0,4