Question

若|x+y-5、+(xy-3)^2=0,则x^2+Y^2=( 注意,是（xy-3）^2,不是（xy-6）^2

Answer 1

∵ |x+y-5|+(xy-3)²=0

∴ x+y-5=0 且 xy-3=0

x+y=5 且 xy=3

∵ x²+y²=(x+y)²-2xy

∴ x²+y²=5²-2×3

=25-6

=19

则x²+y²=( 19 )