SOLUTION: What is an equation of the line that passes through the points (3,3) and (6, -1)? I dont know what to do when I get -4/3 or -1 1/3 Please help

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Question 1164992: What is an equation of the line that passes through the points (3,3) and (6, -1)?
I dont know what to do when I get -4/3 or -1 1/3
Please help

Found 4 solutions by josgarithmetic, solver91311, ikleyn, greenestamps:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
You are asked for an EQUATION.

You have the two needed points so you can calculate slope for the line.
Your equation will have one more constant. You could start with the definition for slope and form your equation that way:

%28y-3%29%2F%28x-3%29=%283-6%29%2F%283-%28-1%29%29
Simplify this, and put it into the equation form that you need.

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


Use the Two-Point Form:



You have already calculated which is the slope, so you could use the Point-Slope Form:




Either way, what you get is an equation of the desired line. You can also put it into Slope-intercept form:



Where

Or Standard form by writing the slope as a fraction and and then the form is



John

My calculator said it, I believe it, that settles it


Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
.

First you calculate the slope using the coordinates of the given points.


The slope  m = %28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29.


In your case x%5B1%5D = 3;  y%5B1%5D = 3;  x%5B2%5D = 6  and  y%5B2%5D = -1.


Therefore, the slope is  m = %28%28-1%29-3%29%2F%286-3%29 = %28-4%29%2F3.


As soon as you have the value of the slope, you write an equation of the line in the form

    y+-+y%5B1%5D = m%2A%28x+-+x%5B1%5D%29 


which is (after substituting the values)

    y - 3 = %28%28-4%29%2F3%29%2A%28x-+3%29.     (1)


At this point, the problem is just solved: you obtained the required equation.


If you want to have it with integer coefficients, multiply both sides of the equation by 3, the denominator.


You will get then an EQUIVALENT equation

    3y - 9 = (-4)*(x-3).      (2)


You can simplify it further

    3y - 9 = -4x + 12,        (3)

or

    4x + 3y = 21.             (4)

The problem is just solved.

What you need understand is that equations  (1),  (2),  (3)  and  (4)  are  EQUIVALENT:
they represent  THE  SAME  STRAIGHT  LINE.

-------------------

It is very elementary and basic skill that every student must develop to the level to solve such problems on his  (or her)
own  AUTOMATICALLY  without asking assistance from outside.

    Similar to as you answer  "4"   when you are asked  "How many is  2*2  ?".

To help you to develop such skills,  the special lesson was created in this site

    - Equation for a straight line having a given slope and passing through a given point

Find there a complete explanation on how to do it and learn the subject once and for all.


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Is everything clear to you in my explanation ?

If you still have questions, do not hesitate to post them to me.



Answer by greenestamps(13199) About Me  (Show Source):
You can put this solution on YOUR website!


You have found that the slope is -4/3.

You can use that, with the coordinates of either point, in the general slope-intercept form of the equation to finish finding the equation.

Note you can also use the general two-point form of the equation, or the point-slope form, as shown by other tutors. Apparently students find those harder to use, because many school districts (unfortunately, in my opinion) now teach only the slope-intercept form.

Anyway.... Here is a solution using your slope and slope-intercept form.

y+=+mx%2Bb

Substitute the slope you found, and the coordinates of either of the given points, to find b.

3+=+%28-4%2F3%29%283%29%2Bb
3+=+-4%2Bb
b+=+7

Now you have both the slope m and the y-intercept b; write the equation.

ANSWER: y+=+%28-4%2F3%29x%2B7