x=2y/3
x+y=30
plug in the value of x in the second equation to have one variable in the equation...
2y/3+y=30
5y/3=30
then multiply 3 on both sides...
5y=90
divide by 5 on both sides...
y=18
and to solve for x you have to plug in y on either equation...
1st way to solve for x:
x+18=30
subtract 18 on both sides...
x=12
2nd way to solve for x:
x=(18)2/3
you then solve...
x=36/3
x=12
answer: 12,18