First let us find the slope of the line using the two points (5,6), (9,14) given.
x1 = 5, y1 = 6, x2 = 9, y2 =14
m = (y2 - y1)/(x2 - x1).
m = (14 - 6)/(9 - 5).
m = 8/4 = 2.
Therefore slope, m = 2.
Using y = mx + c. Slope = m, m = 2.
y = 2x + c
Substituting any of the point (5,6) into the equation, x = 5, y = 6.
6 = 2(5) + c
6 = 10 + c
6-10 = c
-4 = c
c = -4. Substituting into y = mx + c, m =2, c = -4
Therefore y = 2x + (-4).
y = 2x - 4.
Cheers.
