X²(x-1)+x(x-1)²=x(x-1)*(x+x-1)=x(x-1)(2x-1)
А) (м-2н)^2= м^2-4мн+4н^2 б) (5p+3c)^2= 25p^2+30cp+9c^2
В скобках: = 2 / (х-2)(х+2) + 1 / х(2-х) = 2 / (х-2)(х+2) - 1 / х(х-2) = 2х-(х+2) / х(х-2)(х+2) = (х-2) / х(х-2)(х+2) = 1 / х(х+2)
деление 1 / х(х+2) : 1 / (х+2)² = 1 / х(х+2) * (х+2)(х+2) / 1 = (х+2) / х
Если 270 < a < 360, то sin a < 0, cos a > 0.
cos a = 3√11/10, cos^2 a = 9*11/100 = 99/100
sin^2 a = 1 - cos^2 a = 1 - 99/100 = 1/100
sin a = - √(1/100) = -1/10 = -0,1