So something I hadn't encountered with basic polynomials is that it seems to matter how the parentheses are ordered.
e.g whether the answer is typed as (x^2-2)(x-8) vs (x-8)(x^2-2)
the video currently up, and the hints don't explain why though. it tends to get pretty frustrating because it keeps telling me I'm wrong but not how fix my mistakes for the future
Hi lordlouiedor,
I remember when I was taking polynomials and binomials I had to remember that it matters which side the equation for each parenthesis is ordered correctly only for when you are subtracting polynomials because you have to remember that subtraction is not communitive which means that it for subtraction and division it matters on how you order the given values because it changes the entire problem for example:
Multiplication and addition are both communicative properties:
2 + 3 = 5; 3 + 2 = 5
2 * 3 = 6; 3 * 2 = 6
But not for subration and division:
3 - 2 = 1; 2 - 3 = not 1 but -1
20 / 1 = 20; 1 / 20 = not 20 but 1 / 20
Ok so now let's say that for this problem (x^2 - 2) ( x - 8) that x = 2; lets solve:
(x^2 - 2) (x - 8)
x^2(x - 8) - 2(x - 8)
x^3 - 8x^2 - 2x - 16 = 2^3 - 16^2 - 4 - 16
= -268
Now let's reverse the order of the problem and remember that x = 2:
(x - 8) ( x^2 - 2)
x(x^2 - 2) - 8(x^2 - 2)
x^3 - 2x - 8x^2 - 16 = 2^3 - 4 - 16^2 - 16
= -268
Now you may be wondering, well if subtraction is not communicative then why do they both still equal the same? Simply because your subtracting negatives from themselves which always makes an opposite negative equal the reversed version of another opposite negative. While this may be hard to understand I suggest that if you were taking a test on this that you should subtract them in the order that they were originally supposed to be because many mathematicians and the elders of math view this as mathematically inaccurate because it went against or defied the laws of math when it comes to this subject. Even when it's correct it still isn't considered mathematically correct.
Hope this helps and if you have any additional questions to understand better, feel free to ask.
:)
Blue-Ice thank you for responding, I'm actually getting the same answer, I just can't figure out how to tell which order to put the parentheses in? it seems to matter to the program but I can't really figure out a pattern as to how to place them.
I'm going to use another example to see if it helps?
x^5-x^4+3x-3
I then factored to: (x^4+3) (x-1), which was marked as incorrect, though (x-1) (x^4+3) was marked as correct.
I did check the answer, and the pattern I chose for ordering the parenthesis is grouping together the parenthesis that has the greatest common factors for both halves of the equation first so:
x^5-x^4+3x-3 = x^4(x-1) +3(x-1) = (x^4+3) (x-1)
this is the pattern I've chosen for all of my answers for this module, and sometimes it marks my answer as correct, but sometimes it marks it as wrong until I switch the order of the parenthesis (so with this example switching the order would be (x-1)(x^4+3). and I cannot for the life of me figure out how I'm supposed to order them consistently
I see, it appears to be the answering system programmed in that particular way to only accept that way that they put it and it appears to be happening even when you're using different properties. I think that the only way for this to be fixed is if they go in and make it applicable for both orders of the parenthesis. I suggest that you write down the correct way that the system has ordered them then put it that way.
ok, thank you! I just kind of assumed I was missing something lol. I appreciate the help!
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