(8x^2+2x+8)+(3x^3+7x+4)=
8x^2+2x+8+3x^3+7x+4
3x^3+8x^2+(2+7)x+12=
3x^3+8x^2+9x+12
Answer: Option A. 3x^3+8x^2+9x+12
https://www.ck12.org/geometry/faces-edges-and-vertices-of-solids/lesson/Faces-Edges-and-Vertices-of-Solids-MSM7/
The 0 is a represents a rational number.