Finding a equation

Question

 

Find the equation of a line that passes through the points (-3,8) and (-9,-2)

Answer 1

Hi Latoya, to find the line passing through two given points, start by finding the slope of the line represented by the two points.

 

Let m represent the slope, then:

 

m = (y₂ - y₁) / (x₂ - x₁)

 

It does not matter which of the two points is the x₁, y₁, or x₂, y₂.

 

Let (-3, 8) represent x₁, y₁:

 

m = (-2 - 8) / (-9 - (-3))

 

m = -10 / -6

 

m = 5 / 3

 

To find the line, use the point-slope form of the line:

 

y - y₁ = m * (x - x₁)

 

Substitute for m, x₁, and y₁:

 

y - 8 = (5 / 3) * (x - (-3))

 

Multiply the entire equation by 3 to remove the fraction:

 

3y - 24 = 5 * (x + 3)

 

3y -24 = 5x + 15

 

Put into standard form:

 

-5x + 3y = 39

 

Multiply by -1:

 

5x - 3y = 39

 

questions?