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Maths Help please

Hello!
Could someone please help me on q 9 on the posted picture (binomial expansion). n=8 but idk how to get that.
Thank youuuFE3B6CC7-CDEA-457D-9D0A-F5BE8299D587.jpg.jpeg
Original post by Jahayna
Hello!
Could someone please help me on q 9 on the posted picture (binomial expansion). n=8 but idk how to get that.
Thank youuuFE3B6CC7-CDEA-457D-9D0A-F5BE8299D587.jpg.jpeg


The coefficient of x^2 (in terms of n) = 7.

Can you write that equation?
Reply 2
Avatar for Jahayna
Jahayna
OP
11
Original post by BuryMathsTutor
The coefficient of x^2 (in terms of n) = 7.

Can you write that equation?


What do you mean?
I thought of it that way but got stuck:

Y * (x/2)^2 = 7x^2
So y= 14
So 14 must be the 3rd digit of the row n on pascals triangle
So
1
n
14
But idk how to find n afterwards
Reply 3
Avatar for Jahayna
Jahayna
OP
11
Wait nvm i dont think thats right
Original post by Jahayna
What do you mean?
I thought of it that way but got stuck:

Y * (x/2)^2 = 7x^2
So y= 14
So 14 must be the 3rd digit of the row n on pascals triangle
So
1
n
14
But idk how to find n afterwards


First of all (x/2)^2 = x^2/4.

You would be better off writing nC2 rather than Y.
Reply 5
Avatar for Jahayna
Jahayna
OP
11
I really dont get it sorry.
Could you please send me your working out if you can?
Original post by Jahayna
I really dont get it sorry.
Could you please send me your working out if you can?


Here are some brief notes, followed by an example similar to your problem.
Untitled.png34.3KB

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