Answer:
x=21, y=2 OR (21, 2)
Explanation:
solve using substitution:
-1/3x + 9 = 2/3x -12
9 = x -12 (add 1/3 to both sides)
x =21 (add 12 to both sides)
substitute x into first equation to find y ( y= -1/3x +9)
y = -1/3(21) + 9
y = -7 +9
y= 2
Answer : x = 21, y = 2 OR (21 , 2)