90-(1/2x+15)=2x-50 what is x?

A(t)=728(1+0.04)^t how much money did aditya originally invest

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

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10