Respuesta :
[tex]\text{Hello there!}\\ \\ \text{In this question, you need to simplify by adding like terms}\\ \\\text{Both terms are}\,\,b^4,\,\,\text{in which you can combine them}\\\\-23b^4+(-7b^4)\\\\\text{Add them}\\\\-30b^4\\\\\large\boxed{-30b^4}[/tex]