（1）已知（x+56)^2=1234567.求(x+46)(x+66)的值（2）若x=1234567^2,y=1234568,试比较x与y的大小

(1)
(x+46)(x+66)
=（x+56)^2-10^2
=1234567-100
=1234367
(2)
x=1234567^2,y=1234568×1234566
x-y
=1234567^2-1234568×1234566
=1234567^2-1234567^2+1
=1>0
故x>y