Answer:
[tex]-7a^{4} +a -5[/tex]
Step-by-step explanation:
Assuming -2a4+4a4-9a4 are supposed to be [tex]-2a^{4} +-4a^{4} -9a^{4}[/tex]
[tex]-7a^{4} +a -5[/tex]
To simplify, you combine like terms. Like terms are those that have the same variable and same degree. So, combine the terms with the a^4 first, then the a's, and then the ones with just the number.
Hope that makes sense.