Question

Помогите пожалуйста.

Answer 1

$3(a-2)^2-6a(a-2)=3(a^2-4a+4)-6a^2+12a= \ =3a^2-12a+12-6a^2+12a=-3a^2+12=12-3*( sqrt{2} )^2= \ =12-3*2=12-6=6 \ \ ( frac{y}{x} - frac{x}{y} ): frac{2x-2y}{xy^3}= frac{y^2-x^2}{xy} * frac{xy^3}{2(x-y)} = frac{(y-x)(y+x)y^2}{2(x-y)}=- frac{1}{2}(x+y)y^2= \ = - frac{1}{2}(4- sqrt{5} + sqrt{5} )( sqrt{5} )^2=- frac{1}{2}*4*5=-10$

Answer 2

$3(a^2-4a+4)-6a^2+12a=3a^2-12a+12-6a^2+12a=-3a^2+12;$ $-3*( sqrt{2})^2+12=-3*2+12=6$
$frac{y^2- x^{2} }{xy} * frac{xy^3}{2(x-y)}= -frac{(x-y)(x+y)xy^3}{2xy(x-y)}= -frac{(x+y)y^2}{2}= -frac{(4- sqrt{5}+ sqrt{5} )*( sqrt{5})^2 }{2}=- frac{4*5}{2}=-10$