Question

A line contains
the Point (8,3) and
(-4, 9) what is the
equation of the
ine?

Answer 1

y = -
`(1)/(2)` x + 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 ) = (8, 3 ) and (x₂, y₂ ) = (- 4, 9 )

m =
`(9-3)/(-4-8)` =
`(6)/(-12)` = -
`(1)/(2)` , then

y = -
`(1)/(2)` x + c ← is the partial equation

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

using (- 4, 9 ) , then

9 = 2 + c ⇒ c = 9 - 2 = 7

y = -
`(1)/(2)` x + 7 ← equation of line