x=(√5+√3)/2 ,y=(√5-√3)/2x²-4xy+y²=(x²-2xy+y²)-2xy=(x-y)²-2xy=[(√5+√3)/2 -(√5-√3)/2 ]²-2×[(√5+√3)/2] ×[(√5-√3)/2]=(√3)²-2×(√5²-√3²)/4=3-(5...