SOLUTION: How do I use the Two Point Formula to find the equation of the line joining the following pairs of points?: 1. (1,8) and (-1,-20) 2. (2,-1) and (3,5) I have a test on thes

Question 403332: How do I use the Two Point Formula to find the equation of the line joining the following pairs of points?:
1. (1,8) and (-1,-20)
2. (2,-1) and (3,5)
I have a test on these (coordinate geometry) tomorrow and I am still really confused on these. Thank you!
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
# 1

First let's find the slope of the line through the points

and

Start with the slope formula.

Plug in , , , and

Subtract from to get

Subtract from to get

Reduce

So the slope of the line that goes through the points

and

is

Now let's use the point slope formula:

Start with the point slope formula

Plug in , , and

Distribute

Multiply

Add 8 to both sides.

Combine like terms.

So the equation that goes through the points

and

is

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# 2

First let's find the slope of the line through the points

and

Start with the slope formula.

Plug in , , , and

Subtract from to get

Subtract from to get

Reduce

So the slope of the line that goes through the points

and

is

Now let's use the point slope formula:

Start with the point slope formula

Plug in , , and

Rewrite as

Distribute

Multiply

Subtract 1 from both sides.

Combine like terms.

So the equation that goes through the points

and

is

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