Respuesta :

Remark
I didn't know this was a calculus question. How dumb of me.

f(x + h) - f(x)
==========
x + h  - h

50/6 - 51/6 =( -1/6+ h)/h 
The h's will disappear when the limit is taken.

answer - 1/6 which is A. If anyone else answers take their answer.