# Mathematics GCSE Non-Calculator past paper question help

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I'm really confused with a question on a maths past paper, and was wondering if anyone could help me with it. I think this should be a question, not a discussion, but the question thingy isn't working for me :( Anyway, here is the question:

show that 9+11/x+2 = 28/x(x+2) simplifies to 9xsquared+29x-28=0

the mark scheme says:
9x(x + 2) + 11x

9x(x + 2) + 11x = 2

9x
2
+ 18x + 11x = 28

but I cant understand how that works with the 11 becoming 11x and the 9 getting x(x+2)

Thank you :)

Posted: 05-06-11 15:22 by Al

this is how i'd do it

9 +   11/(x+2) =28/x(x+2)

x by x(x+2)

9x(x+2) +  11x(x+2)/(x+2) = 28

the (x + 2) cancel out

so 9x^2+18x +11x=28

9x+29x=28

9x+29x-28=0

Modified once, last modified by Pui Pui on Sun 5th June, 2011 @ 16:02

Posted: 05-06-11 15:35 by Pui Pui

Thank you xD think I get it now :) so you multiply everything on the left by the x(x+2) ?

Posted: 05-06-11 16:06 by Al

yeah so that on the right it leaves 28

Posted: 05-06-11 16:09 by Pui Pui

thanks :) it was how the 9 got the x's aswell that was confusing me

Posted: 05-06-11 16:14 by Al

its alright

good luck

Posted: 05-06-11 16:16 by Pui Pui