Question

Calculate the equation of the line through the points (-1, 1), (4.0), and (24,-4).

A y = 5x + 6
B y= 1/5x + 4/5
C y= -5x + 4
D y= -1/5x +4/5

Answer 1

D

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, 1) and (x₂, y₂ ) = (24, - 4) ← 2 points on the line

m =
`(-4-1)/(24+1)` =
`(-5)/(25)` = -
`(1)/(5)` , then

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

To find c substitute any of the 3 points into the partial equation

Using (4, 0 ) , then

0 = -
`(4)/(5)` + c ⇒ c = 0 +
`(4)/(5)` =
`(4)/(5)`

y = -
`(1)/(5)` x +
`(4)/(5)` → D

Answer 2

Good luck to you! Ask if you have any questions.