Final answer:
To simplify the expression, combine like terms: substract powers of t, combine terms with st, and combine constant terms. The simplified result is -1t^9 - 8st - 9.
Step-by-step explanation:
To simplify the expression by combining like terms, we need to group terms with the same variable and exponent together:
- Combine the t9 terms: (3t9 - 4t9)
- Combine the st terms: (4st - 12st)
- Combine the constant terms: (3 - 12)
Simplifying each group, we get:
The simplified expression is -1t9 - 8st - 9.
When performing these operations, ensure that the terms are dimensionally consistent, meaning they have the same variables to the same powers.