Please explain me what to do on this :)

Which statement about the relative areas of triangle abd and triangle xyz is true

The function ƒ is defined by ƒ(x) = (x + 3)(x + 1). the graph of ƒ in the xy-plane is a parabola. which interval contains the x-coordinate of the vertex of the graph of ƒ?

Can someone me with this problem . show your work .