# Find the values of $k$ for which the line $(k-3)x-(4-k^2)y+k^2-7k+6=0$ is Parallel to the $x$ axis.

$\begin {array} {1 1} (A)\;k=3 & \quad (B)\;k=-3 \\ (C)\;k=\large\frac{1}{3} & \quad (D)\;k=-\large\frac{1}{3} \end {array}$

Toolbox:
• If two lines are parallel then their slopes are equal.
• If the given line is parallel to $x$ - axis then its slope is zero.
The given equation of line is
$(k-3)x-(4-k^2)y+k^2-7k+6=0$
If the given line is parallel to the $x$ - axis , the slope of the given line = slope of the $x$ - axis.
The given line can be written in the form of $y=mx+c$