HELP ME PLS

Solve x-3y-6=0

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Solve for x and select the correct answer

Gia opened two savings accounts at two different banks. one account earns an annual 3.4% simple interest, and the other earns half as much. if she deposited $500 in each account, how much total interest will she have earned in 5 years? a. $34.00 b. $25.50 c. $51.00 d. $510.00