1/2xy - (2x+3y)/6xy
если х= √5 - 1
y=1/12
esli sqrt(5)-1 y=1/12
1/2xy-1/3y-1/2x => (6/sqrt(5)-1)-4-(1/2sqrt(5)-1)
5/sqrt(5)-1-4
5(sqrt(5)+1)/(sqrt(5)-1)*sqrt(5)-1-4
(5sqrt(5)+5)/4-4=> 5(sqrt(5)+1)-16/4=(5sqrt(5)-11)/4