Could i use a "math hack" video on my GCSE paper?

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I have struggled with simultaneous equations. I found this (https://www.youtube.com/watch?v=c527s-oSuhg) video that uses a trick to solve them. I find this method really easy
Could I use this on my exams, and still get the same amount of marks?

Reply 1

Logan12345678

Original post by qwolek

I have struggled with simultaneous equations. I found this (https://www.youtube.com/watch?v=c527s-oSuhg) video that uses a trick to solve them. I find this method really easy
Could I use this on my exams, and still get the same amount of marks?

If it consistently works I don’t see why not, however I cannot officially say yes as I am not an examiner. Personally balancing one unknown and subtracting one equation from another is a lot easier and more understandable for examiners. I doubt you would lose significant marks as when I took my GCSE’s last year, they didn’t really come up (I got an 8).

Reply 2

mqb2766

21

Original post by qwolek

I have struggled with simultaneous equations. I found this (https://www.youtube.com/watch?v=c527s-oSuhg) video that uses a trick to solve them. I find this method really easy
Could I use this on my exams, and still get the same amount of marks?

Looks like its doing linear simultaneous equations using cramers/matrices without writing down the matrices. To fully explain it on a gcse paper would be longer than doing the usual gcse approaches and would require more than gcse knowledge. It would be unlikely to get full marks as written down on the video, as it "pulls the rabbit from the hat" without explaining/understanding whats going on.

You should really try and learn the two basic methods for solving simultaneous equations, so elimination and substitution. Its fairly important to understand the ideas and it also means when you have to solve nonlinear simultaneous equations (circles, lines), you have the fundamentals in place.

(edited 2 months ago)

Reply 3

mqb2766

21

Original post by qwolek

I have struggled with simultaneous equations. I found this (https://www.youtube.com/watch?v=c527s-oSuhg) video that uses a trick to solve them. I find this method really easy
Could I use this on my exams, and still get the same amount of marks?

If youve really struggled with the conventional approach(es), one thing to do is to interpret this method in terms of the conventional approach (elimination). So the first example is
3x + 2y = 18
2x + 5y = 23
The first lines they draw are between the 5(y) on the second row and the first row so consider mulitplying through row 1 by 5 so we get
15x + 10y = 90
2x + 5y = 23
The next lines they draw are between the (original) 2(y) on the first row to the second, so consider multiplying through row 2 by 2 we get
15x + 10y = 90
4x + 10y = 46
Now subtract row 2 from row 1 (to eliminate the 10y) to get
11x = 44
x = 4
Similarly for y, though the usual is to sub x=4 into one of the equations and solve.

So if you understand the way to write down (90-46)/(15-4) on the video, then you can interpret it fairly easily as a couple of row multiplications and a subtraction. So eliminate y and solve for x. The above would get you full marks, though there maybe slightly more efficient ways to solve it once you happy with the approach.

(edited 2 months ago)

Could i use a "math hack" video on my GCSE paper?

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