2sin2xcos2x+cos2xcos4x/sin2x-cos2x=0
cos2x(2sin2xsin2x+cos2xcos2x-sin2xsin2x-cos2xsin2x)/sin2x=0
tg2x(1-1/2sin4x)=0
tg2x=0или sin4x=2
x=пn нет реш
-2а²+3а+2=0, D=9+16=25, √D=5, a₁=2, a₂= -1/2 ⇒ -2a²+3a+2= -2(a-2)(a+1/2)= -(a-2)(2a+1)
2a²+5a+2=0, D=25-16=9, √D=3, a₁=-2, a₂=-1/2, 2a²+5a+2=2(a+2)(a+1/2)=(a+2)(2a+1)
-(a-2)(2a+1) -a+2
------------------- = ------------
(a+2)(2a+1) a+2