(1)根据题意,EP=EQ,即:x²+(6-y)²=y²+(8-x)²∴y=4x3-
73(0<x<8)
(2)若∠PEQ=90°则△ECQ~△PBE,∴
yx=
8-x6-y∴
4x3x=
8-x6-(
4x3-
73)∴x=4