Respuesta :

ghanami
hello : 
PA = PB  or  PA² = PB²
(5-b)²+(4-2)² = (2-b)² + (5-2)²
(5-b)²+4 = (2-b)² + 9
25 -10b +b² + 4  =  4 -4b+b² +9
-6b = -16 
b = 8/3