已知x,y均为实数,且满足xy+x+y=12,x 2 y+xy 2 =32,则x 3 +xy+y 3 =______

已知x,y均为实数,且满足xy+x+y=12,x 2 y+xy 2 =32,则x 3 +xy+y 3 =______.
2025-04-14 20:06:12
推荐回答(1个)
回答1:

xy+x+y=12
xy(x+y)=32

解得
x+y=4
xy=8
x+y=8
xy=4

当得
x+y=4
xy=8
时,t 2 -4t+8=0无解
x+y=8
xy=4
时,
x 3 +xy+y 3 =(x+y)[(x+y) 2 -3xy]+xy=8×(64-12)+4=420.
故答案为420.