1. a) a²-6a+9 b) 4x²+4xy+y² c) 25b²-16x² 2. a) 4a²-8a-a²+8a-16=3a²-16 b) 2(b²+2b+1)-4b=2b²+4b+2-4b=2b²+2 3. a) (x-5)(x+5) b) a(b²-c²)=a(b-c)(b+c) c) -3(a²+2ab+b²)=-3(a+b)² 4. y^4-4y³+4y²-y^4+9y²+4y³+10y=13y²+10y 5. a) (5a-a-3)(5a+a+3)=(4a-3)(6a+3) b) (3a+b)(9a²-3ab+b²) c) (4x²-9)(4x²+9)=(2x-3)(2x+3)(4x²+9) d) (x-y)(x++y)=(x+y)(x-y-1)
α рад=α° π/180°
1°=0,017рад
10°=0,174рад
15°=0,262рад
30°=0,524рад