Question 1029641
Linked image:
*[illustration Screen_Shot_2016_04_16_at_12.01.49_PM.png]

Find the equation of the line passing through the points (3,1) and (7,-7).
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<u>WORK:</u>
First, we need to find the slope (m) of the equation. The formula to find the slope is {{{m=(y2-y1)/(x2-x1)}}}. 

Plug in the numbers into the formula.
{{{m=(-7-1)/(7-3)}}}

Which simplifies to...

{{{m=-8/4}}}

Which is...

{{{m=-2}}}

So now we have the slope. Our equation looks like this so far: {{{y=-2x+b}}}

Now we must find b, which is the y-intercept. 
We can choose one of our points and plug in their x and y values into our current equation. Then, we can solve for b.

Let's use (3,1). 

{{{1=-2*3+b}}}

Solve for b.
Multiply -2 and 3...
{{{1=-6+b}}}
Add 6 to both sides...
{{{7=b}}} or {{{b=7}}}.

Now just plug in 7 for b in our equation.

<u>ANSWER:</u> {{{y=-2x+7}}}