EASY 100 POINTS Which is the missing phrase in Melissa's proof?

O angles ADB and CBD

O angles AOB and COD

O triangles ADB and CBD

O triangles AOB and COD

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

Can someone me out here number 4 plz

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)