The equation for a line is y = mx + b
We can find the slope of the given line to be 3/9 which we can simplify to 1/3
Plug this into the equation for a line
y = 1/3x +b
Now we plug (1,1) in for x and y
1 = 1/3 (1) +b
Solve for b by first subtracting 1/3 from each side
1 - 1/3 = b
2/3 = b
Now we take the equation of a line and plug the slope and b back into the equation to get the answer.
y = 1/3x + 2/3