Answer:
x= -7 y=9
Step-by-step explanation:
3x +9y= 60 [1]
-3x +y=30 [2] rewrite this as the following: y=30+3x
With equation [2] you substitute it into equation [1]
so it will now be: 3x+ 9(30 +3x) =60
3x+270 +27x=60
Group the like terms
3x+27x=60-270
30x=-210
x=-7
Use this answer into the same equation
So: 3(-7)+9y=60
-21 +9y=60
9y=60+21
9y=81
y=9
