1 câu trả lời
Lay ptrinh duoi tru ptrinh tren ta co Dat a=√x,b=√y. Khi do, he tro thanh {a2b+b2a=30(1)a3+b3=35(2) Lay 3.(1)+(2) ta co 3a2b+3b2a+a3+b3=3.30+35 hay 15a2−75a+90=0 Vay a=2 hoac a=3. Tuong ung la b=3 hoac b=2. Vay (a,b)=(2,3) hoac (a,b)=(3,2). Vay (x,y) = (4,9) hoac (x,y) = (9,4).
