Answer:
Solutions are x =4 and y = 1
Step-by-step explanation:
[tex]3x-3y =9[/tex]
In this equation substitute [tex]x=7-3y[/tex], we get
[tex]3(7-3y) -3y=9\\21-9y-3y=9\\-12y= 9-21\\-12y= -12\\y=1[/tex]
now substitute y =1 in x equation,
[tex]x=7-3(1)\\x=7-3\\x=4[/tex]
Solutions are x =4 and y = 1