Find a best linear model for the given data. if needed, round to the nearest tenth

Which equation requires the division property of equality to be solved?

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

What is the answer to this question? i'm a bit stumped. also how do i do it? 5(x - 4) = 2(x + 5)