Verified answer

x = (3a - 7)/a = 3 - 7/a

x nguyên khi 7/a nguyên => a = ± 1

Khong hieu de ra la x = 3a - 7/a hay (3a - 7)/2

Kieu gi thi cung co 4 dap so a = - 1; a = 1; a = - 7; a = 7