Вот! Смотри на фото!!!!!!!!!!!!!!!!!!!!!!!!
x^2-3x : x-2 - 4-3x : x-2 =0
x^2-3x-4+3x=0
x^2-4=0
x^2=4
x1=-2
x2=2
X^3-3x^2+3x-1 =x^3-3x^2*1+3x*1^2-1^3=<span> (x-1)^3
</span>0,25x^2+y^2-xy = (0,5x)^2 -2*0,5x*y+y^2 = (0,5x-y)^2
<span>60x^2+30x+45 =15(4x^2+2x+3)
</span><span>(6x-8)^2= [2(3x-4)]^2 = 4(3x-4)^2
* = 4
</span>
<span>ctg15-tg15 = -[</span>tg(15)-ctg(15)]=-[((sin(15))^2-(cos(15))^2)/(cos(15)*sin(15))]=-[(-cos(30))/(0,5*sin(30))]=2*ctg(30) = 2√3