Can someone please help me and is it correct?

Which of the fallowing best completes the sequence 12,8,5, a) 1 b) 2 c)4 d)0

(if f(x)=4x^2 and g(x)=x+1, find (f o g)(x)

Which best describes the construction of a triangle if given the segment lengths of 2 cm, 3 cm, and 5 cm? a) unique triangle b) cannot be determined c) triangle not possible d) more than one triangle