Answer
This line has an undefined slope and no y-intercept.
Work Step by Step
We are given that $x-7=0$, which can also be written as $x=7$. To find the slope of a line, we can take two points on the line and calculate the slope using the slope formula.
$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$
We know that two points on this line will be (7,2) and (7,4), since all points on this line will have an x-coordinate of 7, no matter the value of y.
$m=\frac{4-2}{7-7}=\frac{2}{0}$
So the slope of this line is undefined. Also, the y-intercept of a line occurs where x=0. However, x always equals 7 on this line, so the line has no y-intercept.