Let's calculate the expressions for the value of b = 4
First expression
[tex]\begin{gathered} 2b+3 \\ 2(4)+3 \\ 8+3 \\ 11 \end{gathered}[/tex]11 baseball bats sold on Tuesday
Second expression
[tex]\begin{gathered} 3b-8 \\ 3(4)-8 \\ 12-8 \\ 4 \end{gathered}[/tex]4 baseball bats sold
The total number of baseball bats is 4+11, therefore 15 baseball bats were sold in total.