he general equation of a line is y = mx+b
m is the slope of the line that you can figure out using the equation: m = (y2-y1)/(x2-x1)
m = (4-2)/(4-1) = 2/3
y = 2/3x+b and you can use either point given to find b:
1) 4 = 2/3(4)+b => b = 4-8/3 = 4/3
2) 2 = 2/3(1)+b => b = 2-2/3 = 4/3
The equation becomes: y = 2/3 x + 4/3