First work out the slope of the line
slope = rise / run if you look at the pointt level with accidents is you see that rise / run - = 3.5 / 7 which is 0.5
The intercept on vertical axis is 1.5
so we can write the equation of the line ( y = mx + b) where m = slope and b = y intercept) as y = 0.5x + 1.5 ( y = accidents and x = number tickets)
so if we plug x = 10 (tickets) into the above
Accidents ( for 10 tickets) = 0.5(10) + 1.5 = 6.5 which we round up to 7.