What is the coefficient of the fourth term in this expression? 6uv + 10tv + t + V

What properties allow transformation to be used as a problem solving tool

To solve the system of equations below, grace isolated the variable y in the first equation and then substituted into the second equation. what was the resulting equation? 3y=12x x^2/4+y^2/9=1

True or false look at the picture pls : /