Question

已知x+y=-4，xy=-12，则

y+1

x+1

+

x+1

y+1

的值是______．

Answer 1

原式=

(y+1)2+(x+1)2

(x+1)(y+1)

=

(x+y)2-2xy+2(x+y)+2

xy+(x+y)+1

，
当x+y=-4，xy=-12时，原式=

(-4)2-2×(-12)+2×(-4)+2

-12-4+1

=-

34

15

．
故答案为：-

34

15

．