In order to evaluate the expression (3b + a²)/b when a = 6 and b = 4, let's use these values on the expression and calculate the final value:
[tex]\frac{3b+a^2}{b}=\frac{3\cdot4+6^2}{4}=\frac{12+36}{4}=\frac{48}{4}=12[/tex]Therefore the value of the expression is 12.