Respuesta :

Square both sides
15f+10=(f+4)^2
15f+10=f^2+8x+16
15f+10-f^2-8x-16=0
-f^2+7f-6=0
f^2-7f+6=0
(f-6)(f-1)=0

ZPP for roots
Answers: 6,1