Question

A line passes through the points (-1,-7) and (7, 1). Write its equation in slope intercept

Answer 1

y = x - 6

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 ) = (- 1, - 7 ) and (x₂, y₂ ) = (7, 1 )

m =
`(1-(-7))/(7-(-1))` =
`(1+7)/(7+1)` =
`(8)/(8)` = 1 , then

y = x + c ← is the partial equation

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

using (7, 1 ) , then

1 = 7 + c ⇒ c = 1 - 7 = - 6

y = x - 6 ← equation of line