Answer:
Step-by-step explanation:(t-by)(4t+3by)
The first term in the first bracket is multiplied by the last bracket
t(4t+3by)=4t^2+3bty
The second term in the first bracket is multiplied by the last bracket
-by(4t+3by)=-4bty-3b^2y^2
Add the results together and simplify where possible
4t^2+3bty-4bty-3b^2y^2=4t^2-bty-3b^2y^2