Find the coefficient of p^4 in the expansion of (p+3)^5*(2p-5)
This is chapter 1A of the maths methods y12 book.
What i've done so far is:
p^4*5 + 10p^3*(3)^2*[2p]
= -5p^4 + 180p^4
However the answer is 105 (which is from 105p^4)
I am confused as to how this answer is derived. Either im doing something wrong or ive missed a part of the mutliplaction.
I checked on my CAS and the answer is defintely 105 so its not a mistake in the book.
Thanks for answer in advanced.