Answer:
B. \(5x^4+5x^3\)
Step-by-step explanation:
Given,
\(f(x) = 5x^3\)
\(g(x) = x + 1\)
We know that,
\((f\cdot g)(x) = f(x).g(x)\)
\(\implies (f\cdot g)(x) = 5x^3(x+1)\)
\(=5x^3.x + 5x^3.1\) ( Distribution property of multiplication )
\(=5x^{3+1}+5x^3\) ( Product of powers property )
\(=5x^4+5x^3\)
Hence, option B is correct.
