Question

What is an equation of the line that passes through the points (−8,2) and (−4,−3)?

Answer 1

y = -
`(5)/(4)` x - 8

Explanation:

The equation of a line in slope- intercept form is

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

To find m use the slope formula

m = ( y₂ - y₁ ) / ( x₂ - x₁ )

with (x₁, y₁ ) = (- 8, 2) and (x₂, y₂ ) = (- 4, - 3)

m =
`(-3-2)/(-4+8)` = -
`(5)/(4)`

y = -
`(5)/(4)` x + c ← is the partial equation

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

using (- 4, - 3), then

- 3 = 5 + c ⇒ c = - 3 - 5 = - 8

y = -
`(5)/(4)` x - 8 ← equation of line