(x + 3) • (x^3 - 3x + 4)
$$\\(x + 3) (x^3 - 3x + 4) = x (x^3 - 3x + 4)\;\; + 3 (x^3 - 3x + 4) \\\\$$
See how I slit up the first bracket?
can you do the expansions yourself now.