Question 49435
This problem uses the formula for the slope backwards to find a missing value.
Start the problem with the equation for slope:
{{{m = (y1 - y2)/(x1 - x2)}}}
Plug in what we know:
x1 = x,
y1 = 5
x2 = 3
y2 = -1
m = 4
So {{{4 = (5 - -1)/(x - 3)}}}
Simplify:  {{{4 = 6/(x - 3)}}}  since 5 - -1 = 6
Solve:
4*(x - 3) = 6   (Cross multiply)
4x - 12 = 6  (Distribute the 4)
4x = 18  (Add 12 to both sides)
x = 18/4 (Divide both sides by 4)
x = 9/2  (Reduce the fraction to lowest terms)