Please answer correctly, Thank You!

Simplify a7/a4 a) 1/a3 b)-a/a2 c)a4/a3 d)a3

Using the side-splitter theorem, daniel wrote a proportion for the segment formed by luke segment de. what is ec?

To solve the system of equations below, pedro isolated the variable y in the first equation and then substituted it into the second equation. what was the resulting equation? { 5y=10x {x^2+y^2=36