Make y the subject of the formula x=a-2by^2

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

Is triangle jkl congruent to triangle rst? if so, what is the scale factor?

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.