Respuesta :

gmany
[tex]k^2+5kf-50f^2=k^2+10kf-5kf-50f^2\\\\=k(k+10f)-5f(k+10f)=(k+10f)(k-5f)\\\\\boxed{Answer:\ A.\ (k+10f)(k-5f)}[/tex]

id go with b honestly

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