Answer
$x^2+4x+3$.
Work Step by Step
The given expression is
$=(x+1)(x+3)$
Distribute $(x+3)$ to each term of $(x+1)$.
$=x(x+3)+1(x+3)$
Use distributive property.
$=x(x)+x(3)+1(x)+1(3)$
Multiply.
$=x^2+3x+x+3$
Combine like terms.
$=x^2+4x+3$
Hence, the product is $x^2+4x+3$.
