This is a question from a test that I have done. I have the answer but am unsure of the working.(adsbygoogle = window.adsbygoogle || []).push({});

consider the expansion of (x^2 - 2)^5

a) write the down the number of terms in this expansion

b) the first 4 terms of the expansion in descending powers of x are

x^10 - 10x^8 + 40x^6 + Ax^4 + ...

Find the value of A

For part a) I got the answer as 5 but apparantly it is 6 and I am not sure why.

I am stuck how to do part b) but know the answer is -80

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# Expansion of (x^2 - 2)^5

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