3200 - 100 %
x - 30%
x = 30 x 3200 ÷ 100 = 960 (RUB)
3200 - 960 = 2 240 (цена) - коньков со скидкой
<span>c^3 - 16c=c(c</span>²-16)=c(c-4)(c+4)<span>
3a^2 - 6ab + 3b^2=3(a</span>²<span>-2ab+b</span>²)=3(a-b)(a-b)<span>
y^2 - x^2 - 6x - 9=y</span>²-(x+3)²=(y+x+3)(y-x-3)<span>
81a^4 - 1=(9a</span>²-1)(9a²+1)=(3a-1)(3a+1)(9a²+1)
Решение:
2sin(5П/18)сos(П/3)/-2sinп/3sin5П/18=-ctgП/3=-1/sqrt(3).