How to plot solutions on a number line?

There is a line with slope 1/a going through the point (a, a²). find the equation of the line perpendicular to this line at this point. (don’t let this problem intimidate you! solve the problem as you would if i’d given you specific values. just use variables instead.)

True or false look at the picture pls : /

The function show two sisters' savings account and the rate at which they plan to deposit money