Answer:

Note: the slope is 1/3 and the y intercept is 1/3
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Step-by-step explanation:
First we need the slope of the line through the two points. Use the slope formula
m = (y2 - y1)/(x2 - x1)
m = (2-1)/(5-2)
m = 1/3
The slope is m = 1/3
Use this slope, along with one of the points. I'll use the point (x,y) = (2,1). Plug these three values into the equation y = mx+b and then solve for b
y = mx+b
1 = (1/3)(2)+b
1 = 2/3+b
1-2/3 = 2/3+b-2/3
1 - 2/3 = b
b = 1 - 2/3
b = 3/3 - 2/3
b = 1/3
So the slope and y intercept are
m = 1/3
b = 1/3
Therefore the equation is
