Math Help Please

Can someone please help me with this problem 

Find $g(x)$, with terms in order of decreasing degree, if we have that $8x^4-7x^2+8x-7+g(x)=x + 1.$

I think it might be $g(x)=-8x^4+7x^2-7x + 8$ because I just subtracted $8x^4-7x^2+8x-7$ from both sides