Explanation:
answers to what questions ?
do you mean you need the equations of the lines in the charts ?
if that's the case :
I am always looking for points on the coordinate grid that seem to have whole numbers as x and y coordinates.
I am using the slope-intercept form
y = ax + b
with "a" being the slope (the ratio of "y coordinate change / x coordinate change").
b being the y-intercept (the y value when x = 0).
2.
I see (0, 3) and (3, 4). and then (6, 5) and (9, 6).
x changes by +3 (from e.g. 0 to 3).
y changes by +1 (from e.g. 3 to 4).
so, the slope is +1/+3 = 1/3
the first point gives us the y-intercept directly : 3.
the line is :
y = x/3 + 3
3.
on the graphic there seems to be no precise whole number coordinate.
the closest I could find are (0, 9) and (8, 4).
then x changes by +8 (from 0 to 8).
y changes by -5 (from 9 to 4).
the slope is then : -5/8
the first point gives us the y-intersect again : 9.
the line is :
y = -5x/8 + 9
4.
it seems we have (0, 0) and (4, 3).
x changes by +4 (from 0 to 4).
y changes by +3 (from 0 to 3).
the slope is +3/+4 = 3/4.
the first point gives us the y-intercept directly : 0.
the line is :
y = 3x/4
5.
it seems we have (0, 6) and (2, 5).
x changes by +2 (from 0 to 2).
y changes by -1 (from 6 to 5).
the slope is -1/+2 = -1/2.
the first point gives us the y-intercept directly : 6.
the line is :
y = -x/2 + 6
6.
it seems we have (0, 5) and (5, 7).
x changes by +5 (from 0 to 5).
y changes by +2 (from 5 to 7).
the slope is +7/+5 = 7/5.
the first point gives us the y-intercept directly : 5.
the line is :
y = 7x/5 + 5
7.
it seems we have (0, 9) and (1, 7).
x changes by +1 (from 0 to 1).
y changes by -2 (from 9 to 7).
the slope is -2/+1 = -2
the first point gives us the y-intercept directly : 9.
the line is :
y = -2x + 9