We are asked to find the number of common roots between the two equations:
\[
x^3 + 3x^2 + 4x + 5 = 0
\]
and
\[
x^4 + 2x^3 + 7x + 3 = 0
\]
By solving both equations (either graphically or algebraically), we find that they have no common roots.
Thus, the number of common roots is 0.