Question 5428
You are correct in your setup, except for one point--you forgot that Irina's age is changing as well as Deac's age.   

x= Deac's age now
y= Irina's age now


x+7= 2(y+7)
x-4= 3(y-4)


I recommend that you solve for x in both of the above equations, and set them equal to each other in order to solve for y.  I get y= 15, which seems correct.


R^2 at SCC