We can use the slope-intercept form of the equation of a line, y = mx + b, where m is the slope and b is the y-intercept.
From the graph, we see the line crosses the y-axis at y = 15. That means the y-intercept is 15, and we have so far y = mx + 15.
Now we need the slope. On the graph we see that for every 3 units up in y, there is 1 unit to the right in x. The slope is 3/1 = 3. m = 3. Now we add the slope to the equation.
y = 3x + 15
Answer: y = 3x + 15