# Writing an equation of a line in standard form

• Sep 20th 2007, 03:50 PM
trancefanatic
Writing an equation of a line in standard form
Recall how to write an equation of a line in standard form given 2 points
• no fractions
• no decimals
• x is positive
**********
1) (1/2,-2); (1/2,5)

2) (3,-6); (10,-6)
i planned to use m=y2-y1/x2-x1, then y=mx+b, and then put it into Ax+By=C. but after using m=y2-y1/x2-x1, i kept getting a fraction: 7/0 for #1 and 0/7 for #2. i can't remember which one is indefinite, but i'm stuck on the first step because the teacher said no fractions... thanks in advance
• Sep 20th 2007, 04:18 PM
Plato
Line #1 is simply: $2x=1$.
Some textbooks insist that standard form is: $Ax+By+C=0,\;A>0$.
Be sure to see what your text says.
• Sep 20th 2007, 05:18 PM
trancefanatic
Quote:

Originally Posted by Plato
Line #1 is simply: $2x=1$.
Some textbooks insist that standard form is: $Ax+By+C=0,\;A>0$.
Be sure to see what your text says.

2x=1? the thing is that the publisher hasn't sent our textbooks yet, we are working blindly w/problems she throws at us. she hasn't explained it either because it's, "review." may i ask the steps you would use or how you got 2x=1?
• Sep 20th 2007, 05:35 PM
Plato
Quote:

Originally Posted by trancefanatic
2x=1? the thing is that the publisher hasn't sent our textbooks yet, we are working blindly w/problems she throws at us. she hasn't explained it either because it's, "review." may i ask the steps you would use or how you got 2x=1?

Bless you my friend, you are the casualty of fraud.
If you want to take legal action, I will take you side.
The whole “online teaching of mathematic is a scam”!
• Sep 20th 2007, 05:39 PM
trancefanatic
Quote:

Originally Posted by Plato
Bless you my friend, you are the casualty of fraud.
If you want to take legal action, I will take you side.
The whole “online teaching of mathematic is a scam”!

..............wait, what???!
• Sep 20th 2007, 07:02 PM
Plato
Quote:

Originally Posted by trancefanatic
..............wait, what???!

Here is 47 years of teaching experience speaking.
If you or the institution offering an online course in mathematics thinks that such a course will teach you the equivalent of an on campus course, then I have a big bridge in NY to sell you both for \$1.

Any online course in mathematics is a joke!
It cannot be done. You can pay your money. You can even get a passing grade. But you will not understand the material that is in 70% of the cases a prerequisite to the rest of your life. WHY TAKE THE CHANCE
• Sep 20th 2007, 07:15 PM
trancefanatic
Well, this might make you laugh. It's not an online course! The institution just opened a few weeks ago and haven't received text books yet. Why? I don't know, but all I know is that this teacher makes no sense to me whatsoever because of her extreme methods that are "outside of the box." Although these problems are due tomorrow... I think it'd be a risk I'd have to take (F).

Oh well.
• Sep 21st 2007, 05:59 AM
topsquark
Quote:

Originally Posted by trancefanatic
Recall how to write an equation of a line in standard form given 2 points
• no fractions
• no decimals
• x is positive
**********
1) (1/2,-2); (1/2,5)

2) (3,-6); (10,-6)
i planned to use m=y2-y1/x2-x1, then y=mx+b, and then put it into Ax+By=C. but after using m=y2-y1/x2-x1, i kept getting a fraction: 7/0 for #1 and 0/7 for #2. i can't remember which one is indefinite, but i'm stuck on the first step because the teacher said no fractions... thanks in advance

1) Note that any points on a line passing though these points is going to have the same x value. Thus $x = \frac{1}{2}$. Now put that in standard form without any fractions.

2) Note that any points on a line passing through these points is going to have the same y value. etc.

-Dan