$\left(4 x^{5}\right) \times\left(2 x^{3}\right)$
\(\boxed{8x^8}\)
Step 1 :Multiply the coefficients: \(4 \times 2 = 8\)
Step 2 :Add the exponents: \(5 + 3 = 8\)
Step 3 :Combine the results: \(8x^8\)
Step 4 :\(\boxed{8x^8}\)