#### Answer

$n=11$

#### Work Step by Step

$5(n-3)=7+3n$ $\longrightarrow$distributive property
$5n-15=7+3n$ $\longrightarrow$addition property
$5n-15+15-3n=7+3n+15-3n$ $\longrightarrow$combine like terms
$2n=22$ $\longrightarrow$multiplication property
$2n\div2=22\div2$ $\longrightarrow$simplify
$n=11$