What additional information would be necessary to prove that the two triangles, XBY and ZAY, are congruent

I’m stuck on this equation, anyone got the answer?

Asporting good store is offering 30 percent off of the original price(x) of football cleats. the discount will be reduced by an another $7 before sales tax.

If 7x=9y, y/z = 7/5 , then x/z = (a) 2/7 (b) 7/9 (c) 9/5 (d) 9/7 (e) 5/9