Question

AB describes a line.

AB has a gradient of 3 and passes through the point (1, 15)
Find the equation of line AB,

Answer 1

y = 3x + 12

Explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Here m = 3 , then

y = 3x + c ← is the partial equation

To find c substitute (1, 15) into the partial equation

15 = 3 + c ⇒ c = 15 - 3 = 12

y = 3x + 12 ← equation of line AB