Answer:
[tex]y^{12} + b^{8} \\OR\\12y + 8b[/tex]
Step-by-step explanation:
If the statement is
[tex]y^{12} + b^{16-8} \\y^{12} + b^{8} \\[/tex]this can't be more simplified
If the statement is
[tex]y{12} + b{16-8} \\y{12} + b{8} \\\\rearrange\\12y + 8b[/tex]