Respuesta :
x+3y=7
Substitute -20 for x
-20+3y=7
Add 20 to both sides
3y=27
Divide 3 on both sides
Final Answer: y=9
Substitute -20 for x
-20+3y=7
Add 20 to both sides
3y=27
Divide 3 on both sides
Final Answer: y=9