the line through (2,3) (4,5)
write an equation of each line in standard form with interger coefficients
m = (y2 - y1) / (x2 - x1)
m = (5 - 3) / (4 - 2)
m = 2/2
m = 1
b = y - mx
b = 5 - (1)(4)
b = 5 - 4
b = 1
Standard form: Ax + By = C
y = mx + b << slope-intercept form
-mx + y = b
The equation is -x + y = 1
Check it with the given points.
(2, 3) -2 + 3 = 1 checks
(4, 5) -4 + 5 = 1 checks