Let x = the # of purle marbles
Let y = the # of green marbles
x + y = 39
x = 5y - 9
Substitute the value of x into the first equation
5y - 9 + y = 39
Add like terms
6y - 9 = 39
Add 9 to both sides
6y = 48
Divide both sides by 6
y = 8
Substitute the value of y into the second equation of x = 5y - 9
x = 5 ( 8 ) -9
x = 40 -9
x = 31
Therefore the answer is 31 puple marbles and 8 green marbles.
