(5a+0.4)^2=25a^2+4a+1.6
(2x-1)(4x^2+2x+1)=2x^3+2x^2+2x-4x^2-2x-1=2x^3-2x^2-1
16х²-9-(16х²-8x+1)=3x
16x²-9-16x²+8x-1-3x=0
5x=10
x=2
А)=(sin^2(x) - 2sinx*cosx+cos^2(x))\(sin2x-1) = (1-sin2x)\(sin2x-1) = -1
б)=(2sina+2sin^2(a)+2cos^2(a))\(1+sina) = (2sina+2)\(1+sina) = 2