What is the equation, in slope-intercept form, of the line that
contains the points (3, -4) and (5, -6)?

First, let's find the slope of those two points:
slope = (-4 - - 6) / (3 - 5)
slope = 2 / -2
slope = -1
Next, we'll use the slope-intercept form equation and plug in one point to find the value of b. In this case, I will use the point (3,-4):
-4 = -1(3) + b
-4 = -3 + b
b = -1
Finally, with our values of b and the slope, we can plug those into the slope-intercept form to get our equation:
y = -x - 1
Hope this helps!! :)