Final answer:
The expression −3t^2−2t(4s−9t)+7st can be simplified to 15t^2-st.
Step-by-step explanation:
This expression is a quadratic equation in the form of −3t^2−2t(4s−9t)+7st. To simplify, we can start by distributing the -2t across the terms inside the parentheses:
−3t^2−8st+18t^2+7st
Combining like terms, we get:
15t^2-st
So, the expression −3t^2−2t(4s−9t)+7st in simplest form is 15t^2-st.