Solution: Let DP=x, then AP=7-x, and CE∨AD and AB are in E, ∫AB∨CD, ∠A=90? ,∴∠D=90？ ∴∠AEC=90？

∴ Quadrilateral AECD is rectangular, CE=AD=7, AE=CD=2, BE=AB-AE= 1.

∴BC？ = Yes? +CE？ = 1+49=50

CP？ =CD？ +DP？ =4+x？

BP？ =AP？ +AB？ =(7-x)？ +9

∵CP？ +BP？ =BC？ ,∴4+x？ +(7-x)？ +9=50

Tidy up, x? -7x+6=0, solution, x= 1 or x=6.

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