Find Undefined

1.  C

$\dfrac{3+x}{x-3}=\dfrac{3+3}{3-3}=\dfrac{6}{0}=$ undefined.

2. C

$\dfrac{a-2}{-a+2}=\dfrac{2-2}{-(2)+2}=\dfrac{0}{0}=$ undefined.

3.  A

$\dfrac{2(y+2)}{-3(y-2)}=\dfrac{2(2+2)}{-3(2-2}=\dfrac{8}{0}=$ undefined.

4.  1 or 2

$\eqalign{g(x)=&\dfrac{1}{(x-4)^2+5(x-4)+6}\\&(x-4)(x-4)+5(x-4)+6\\&x^2-8x+16+5x-20+6\\&x^2-3x+2\\&(x-2)(x-1)\\&x-2=0\\&x=2\\&x-1=0\\&x=1}$

x = 1 or 2