Question

Which of the following is an equation of the line through (2, 3) and (−1, −12

Answer 1

y = 5x - 7

Explanation:

The equation of a line in slope- intercept form is

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

Calculate m using the slope formula

m =
`(y_(2)-y_(1) )/(x_(2)-x_(1) )`

with (x₁, y₁ ) = (2, 3 ) and (x₂, y₂ ) = (- 1, - 12 )

m =
`(-12-3)/(-1-2)` =
`(-15)/(-3)` = 5 , then

y = 5x + c ← is the partial equation

To find c substitute either of the 2 points into the partial equation

Using (2, 3 )

3 = 10 + c ⇒ c = 3 - 10 = - 7

y = 5x - 7 ← equation of line