book Maths Puzzle Numerical Ability

i do not understand polynomials AT ALL so any help would greatly be appreciated
(2x squared +3x - 5)+ (7x squared -x+7)=
i tried it and this is what i got for the answer
9xsquar

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book Other Question

x 2x+3
--- = -------
4 15
[14 + (-3)]7=14x____ +______ x 7