Respuesta :
Answer:
9
Step-by-step explanation:
6x + 2y = 30
9x - 4y = 3
if we double the first equation and add up to second one, we cancel 4y:
- 12x+9x=60+3 ⇒ 21x=63 ⇒ x=3
now we can find y:
- 6*3+2y=30 ⇒ 2y= 30- 18 ⇒ 2y= 12 ⇒ y=6
finally, x+y
- x+y= 3+6= 9