2 days late, but the answer is no solution. solving a system of equations means finding where they intersect, but by looking at these equations, you know that they never intersect--they're parallel.
they share a slope (2), making them either parallel or "the same line", but the different x-intercepts (9 and -9) mean that they're different lines. they have no solution, or no intersection point, because they're parallel lines.
