Find any points of discontinuity for the rational function. What are the points of discontinuity? Are they all removable?
y = (x-7)(x-3) / x^2-10x+21

A. x = 1, x = –8, x = –2; yes
B. x = 7, x = 3; yes
C. x = –7, x = –3; no
D. x = –1, x = 8, x = 2; no

Question

Find any points of discontinuity for the rational function. What are the points of discontinuity? Are they all removable? 
y = (x-7)(x-3) / x^2-10x+21

A. x = 1, x = –8, x = –2; yes	
B. x = 7, x = 3; yes	
C. x = –7, x = –3; no	
D. x = –1, x = 8, x = 2; no

phoenixfire · Answer

I'm not entirely sure. But if you expand (x-7)(x-3) you get x^2-10x+21. so basically that equation breaks down to y=1. So there isn't any discontinuity. 
However, if you choose B. x=7, x=3 either of those will result in y=0 which is weird. 
So, I would say they are removable and the answer to your question is B.