Question

Write an equation for the line that passes through (-5, 4) and (-4, 2).

Answer 1

y = - 2x - 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 ) = (- 5, 4) and (x₂, y₂ ) = (- 4, 2)

m =
`(2-4)/(-4-(-5))` =
`(-2)/(-4+5)` =
`(-2)/(1)` = - 2 , then

y = - 2x + c ← is the partial equation

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

Using (- 4, 2 ) , then

2 = 8 + c ⇒ c = 2 - 8 = - 6

y = - 2x - 6 ← equation of line