How to find the general form (Ax-By-C = 0) of a line with an undefined slope This is how the question reads:
"The equation of the line that goes through the points (3, -6) and (3, 10) can be written in general form Ax + By + C = 0 where A = _ B = _ and C = ____" I know the answer for B is 0 but am unable to find the solutions for A and B. Please help!

This appears to be a vertical line. The x-coordinate is always equal to $3$, so we can write $x=3$. This is in fact the equation of the line. Let's put it into general form.
$$
\begin{align}
&x=3 \\
&x-3=0 \\
&1x-0y-3=0 \\
\end{align}
$$
Therefore $A=1$, $B=0$ and $C=-3$.
