Which symbol commonly denotes slope and what does it represent?

On a grid you identify two grid points on a line at coordinates $(2,-1)$ and $(6,3)$. Using rise divided by run, what is the slope?

Starting at point (2, 1), apply the slope $\frac{4}{-5}$ (i.e., the negative sign is in the denominator) as a rise/run instruction. Which point do you reach after applying that single step correctly?

Which of the following descriptions correctly identifies the slope of a vertical line and explains why?

A wheelchair ramp must rise 2 feet for every 12 feet horizontally to meet a building entrance. Starting from ground-level point (0,0), write the slope and find the coordinates of the point at the top of a 36-foot section of ramp, then state the slope-intercept equation of the ramp line.