What is the slope and intercept of 7x=5?

$7 x = 5$ is the equation of a vertical line and as such its slope is undefined.
$7 x = 5 \textcolor{w h i t e}{\text{XX")hArrcolor(white)("XX}} x = \frac{5}{7}$
The value of $x$ doesn't change no matter what vales are chosen for $y$
So the slope, defined as $\left(\text{change in "y)/("change in } x\right)$