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simplify equ -C4

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Reply 1
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Qer
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Capture.PNG

I am stuck in this part from last 30 mins .I am not getting this equ (high lighted)
I got 500x^2 -3776 x +5165

here is my working
1296(10-x/20)=100x^2 -820x +1681
648-324/5x=100x^2-820x+1681
100x^2 -3776/5x^2 +1033=0
500x^2 -3776x+5165
Original post by Qer
Capture.PNG

I am stuck in this part from last 30 mins .I am not getting this equ (high lighted)
I got 500x^2 -3776 x +5165


here is my working
1296(10-x/20)=100x^2 -820x +1681
648-324/5x=100x^2-820x+1681
100x^2 -3776/5x^2 +1033=0
500x^2 -3776x+5165

How did you go from the first line to the second? Might wanna double check that.
Reply 3
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Qer
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Original post by Radioactivedecay
How did you go from the first line to the second? Might wanna double check that.


1296((10-x)/20)=100x^2 -820x +1681
648-324/5x=100x^2-820x+1681

1296 Multiply 1/20(10-x) =324/5

324/5 multiply (10-x) = 648 -324/5 x
Original post by Qer
1296((10-x)/20)=100x^2 -820x +1681
648-324/5x=100x^2-820x+1681

1296 Multiply 1/20(10-x) =324/5

324/5 multiply (10-x) = 648 -324/5 x


I dont see how you went from 1296((10-x)/20) to 648-324/5x. You went from having the x on top to having it on the bottom??
Reply 5
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Qer
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Original post by Radioactivedecay
I dont see how you went from 1296((10-x)/20) to 648-324/5x. You went from having the x on top to having it on the bottom??


nope, it is still on the top.
648 -(324/5)x


that was a typing error
Original post by Qer
nope, it is still on the top.
648 -(324/5)x


that was a typing error

In that case, your simplifying is correct. You must have made an error earlier.
Reply 7
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Qer
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Original post by Radioactivedecay
In that case, your simplifying is correct. You must have made an error earlier.


Capture.PNG
I got exactly that equ but when i simplify it I got a different answer, up to that equ all my working is 100%perfect.....
Original post by Qer
Capture.PNG
I got exactly that equ but when i simplify it I got a different answer, up to that equ all my working is 100%perfect.....


Yeah your working is fine. Mark scheme is definetely wrong here, they expanded wrong.
Reply 9
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Qer
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Original post by Radioactivedecay
Yeah your working is fine. Mark scheme is definetely wrong here, they expanded wrong.


yeah I think so
thanks for help
On the first line of the printed working, it looks as though "36" should actually be "18", i.e. 6 x 3.

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