Respuesta :

x=12-y (a)

2x+3y=29 (b)

Replace (a) in (b), and solve for y:

2(12-y)+3y =29

24-2y+3y=29

24+y= 29

y=29-24

y=5

Replace y on (a), and solve for x:

x=12-(5)

x= 7

Solution: x=7, y=5