Explanation:
I assume you need the slope-intercept form
y = ax + b
"a" is the slope of the line, "b" is the y- intercept (the y-value when x = 0).
the slope is the ratio (y coordinate change / x coordinate change) when going from one point on the line to another.
for l we go from (5, 20) to (8, 80) and get
x changes by +3 (from 5 to 8)
y changes by +60 (from 20 to 80)
the slope is therefore
+60/+3 = 20/1 = 20 = a
so, we have
y = 20x + b
the y- intercept looks to be -80, but to be sure we use a point (e.g. 5, 20)
20 = 20×5 + b = 100 + b
b = -80
yes, the equation is
y = 20x - 80
for m we go from (5, 20) to (8, -40) and get
x changes by +3 (from 5 to 8)
y changes by -60 (from 20 to -40)
the slope is
-60/+3 = -20/1 = -20
we have therefore
y = -20x + b
we use the same trick for b as before
20 = -20×5 + b = -100 + b
b = 120
and our full equation is
y = -20x + 120