Question

In Exercises 13-16, write an equation in slope-intercept form of the line shown. (See Example 3.)

(-4, 0)
-2
Ay
2 x
(1,-5)

Answer 1

y = - x - 4

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 ) = (- 4, 0) and (x₂, y₂ ) = (1, - 5) ← 2 points on the line

m =
`(-5-0)/(1-(-4))` =
`(-5)/(1+4)` =
`(-5)/(5)` = - 1

the line crosses the y- axis at (0, - 4 ) ⇒ c = - 4

y = - x - 4 ← equation of line