X^2-3x=0; x*(x-3)=0; x=0 или x-3=0. x1=0, x2=3. Ответ: x1=0, x2=3.
5x^4-20x^2=0
5x^2*(x^2-4)=0
5x^2*(x-2)*(x+2)=0
x^2*(x-2)*(x+2)=0
x^2=0 x1=0
x-2=0 x2=2
x+2=0 x3=-2
M[(x-y)³+(y-z)³-(x-z)³]=m(x³-3x²y+3xy²-y³+y³-3y²z+3yz²-z³-x³+3x²z-3xz²+z³)=
=-3m(x²y-xy²+y²z-yz²-x²z+xz²)
sin (-a) = -sin(a) cos (-a) = cos(a)
табличные значения:
sin(-30) = -sin(30) = -1/2
cos(30) = V3 / 2
cos(-45) = cos(45) = V2 / 2 = sin(45)
tg(30) = V3 / 3 = ctg(60)
а теперь подставим...
... = (-1/2 - V3 / 2)^2 / (3*2/4 - 6*3/9) = (-1-V3)^2 / 4 * (-2) = (1+2V3+3)/(-2) = -2 - V3