What is the mean of all three-digit positive integers whose digits are in the set (2,0,1,9)

Assemble the proof by dragging tiles to the statements and reasons column

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