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Lizzie

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So umm just throwing this out there but... Anyone good at algebra 1 willing to help me with a prob?
 

Lizzie

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Sweet thanks!!

Explain in words how to graph the line 3x - 5y = 10 to someone who has never taken an Algebra class. Use correct vocabulary as you explain the process and what the solution (the graph) tells you about the equation of the line.
 

Point

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Ok, here goes nothing!

Since you're solving for y, move the 3x to the right side. The 5y is negative (3x - 5y) so it becomes

-5y = -3x + 10

Divide by -5 to get y by itself.

y = -3x/-5 + 10/-5

Work it out. -3 and -5 cancel to 3/5. Leave it as a fraction, since they're most precise. 10/-5 becomes -2.

y = (3/5)x - 2

To find the y-intercept, or where the line meets y, take the number that's added or subtracted from the x - in this case, it's -2.

The slope of the line is whatever the x is multiplied by. In this case it's 3/5, or up three units, right five units.
 
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Lizzie

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Sweet!! Thanks!! I soooo suck at math
 

Point

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Hopefully you don't just take that and write it down - study hard. I'm bad at math but if I study enough I do just fine.
 
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Yup... the way Point has done it is generally the most effective way to solve these sorts of problems.

However I got y = (3/5)x - 2 ... minus 2!

It always helps to use a method where you deal with as little negatives as possible!

Because you got 3x - 5y = 10
3x = 10 + 5y (bring the 5y over, get rid of all the negatives)
3x - 10 = 5y (move the 10 to the other side - negative is unavoidable - to isolate the 5y)
(3/5)x - 2 = y (divide through by 5 to get the function of y.)

I think you just put in the wrong sign Point. :)



Simply make the equation as a function of y (That is, have it as y = ...)

As a side note, it always helps to know general formula's too.

You (should :p) know the general equation of a straight line is y = mx + c

Where: m = gradient of the line
x = your variable
c = a constant, and also where the line crosses the y-axis.
 

Point

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Oh, crap! I guess I still need practice too! :D
 

Gingy

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I like your cookie... That's all I have to say
 

Peachy

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Oh, crap! I guess I still need practice too! :D
I always tell my students when they turned negative numbers into positive ones: "If you ever open a bank, please let me know immediately - I want to be your first customer!" :-D

Peachy
 

Squigma

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Aww man, I hate the questions that ask you to explain stuff in words. It's algebra, not English - I just wanna work it out, I don't wanna explain everything I'm doing using correct vocabulary!
 

Peachy

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Aww man, I hate the questions that ask you to explain stuff in words. It's algebra, not English - I just wanna work it out, I don't wanna explain everything I'm doing using correct vocabulary!
In school and science, you have to however. Because you're not doing the calculations for yourself, but for others to understand. The teacher in school has to know that you have understood the concept and didn't just copy the correct answer from the dude sitting next to you, while scientic papers want to prove a point or a certain theorem, and you cannot prove anything if your paper does not give people an idea how your theorem works, and that requires words.

Peachy
 
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In school and science, you have to however. Because you're not doing the calculations for yourself, but for others to understand. The teacher in school has to know that you have understood the concept and didn't just copy the correct answer from the dude sitting next to you, while scientic papers want to prove a point or a certain theorem, and you cannot prove anything if your paper does not give people an idea how your theorem works, and that requires words.

Peachy
That, and the fact that all real world problems eventually boil down to asking yourself - in words, obviously - what the problem is and how you should solve it. It was my physics teacher who put it so bluntly, "There's no point in doing a problem if you don't know and understand the theory behind it and what it represents".

You could give someone the equation E = mc^2, and say that m = 3 and c = 3×10^8, and to solve it for it for E. No problem, even a 3rd grader could do that. But actually understanding what you've just done is a whole 'nother game.

I don't know about other country's, but here I know that worded maths problems are a core part of the curriculum. It shows that you understand the problem and can apply your understanding of maths to solve the problem.
 

Charlie

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and what the solution (the graph) tells you about the equation of the line.
I assume that means you have to specifically say that the gradient is 3/4, and say that the -2 means that it crossed the Y axis at -2.

You could sketch the graph to prove that you are right.
 

Lizzie

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lol that's great peachy!! About the bank thing I mean lol
 
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Squigma

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I assume that means you have to specifically say that the gradient is 3/4, and say that the -2 means that it crossed the Y axis at -2.

You could sketch the graph to prove that you are right.
How'd you do that? Do you have some magic graph-drawing software?
 

recovery

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How'd you do that? Do you have some magic graph-drawing software?
Unfortunately I cannot see the image. But at my school we use OmniGraph on the computer. You can google it and download the trial. Its pretty basic and simple and should do what you need.

Tell us when you cracked straight line and want to go to quadratics. That is where you'll have an X squareds in your equation. E.g. x^2 + 2x +1 =y

I do not know what you view is on maths. But I really enjoy it. And hope you do to. I know it may seem sad to some people. But the satisfaction of being able to solve problems with maths and logical thinking is really satisfying!
 

d4l

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I always tell my students when they turned negative numbers into positive ones: "If you ever open a bank, please let me know immediately - I want to be your first customer!" :-D

Peachy
Your a teacher peachy?
 
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