The y-intercept of a polynomial is found by evaluating the function at \( x = 0 \).
Given the polynomial:
\[ f(x) = x^6 - 2x^7 + 3x + 3 + 6x^3 \]
Evaluating at \( x = 0 \):
\[ f(0) = (0)^6 - 2(0)^7 + 3(0) + 3 + 6(0)^3 = 0 - 0 + 0 + 3 + 0 = 3 \]
Therefore, the y-intercept of the polynomial is:
3