Final answer:
To multiply (5x+1)(x+4), use the distributive property to expand and combine like terms.
Step-by-step explanation:
To multiply (5x+1)(x+4), we can use the distributive property and multiply each term in the first expression by each term in the second expression:
(5x+1)(x+4) = 5x(x+4) + 1(x+4)
Using the distributive property again, we can expand:
5x(x+4) + 1(x+4) = 5x^2 + 20x + x + 4
Combine like terms:
5x^2 + 20x + x + 4 = 5x^2 + 21x + 4
Therefore, the expanded form of (5x+1)(x+4) is 5x^2 + 21x + 4.
Learn more about Multiplying expressions using the distributive property